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Page 1: ALBERTA DIABETE S ATLA S 2007

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ISBN: 978-0-9780024-4-2

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Published by the Institute of Health Economics.

Design: Dimensions Graphic Studio

How to cite the publication:The production of the Alberta Diabetes Atlas 2007 was a collaborative venture. Accordingly, in addition to the book title and publisher, to give credit to individual authors, please cite individual chapter using chapter authors and title. For example, for Chapter 2: Jeffrey A. Johnson, Stephanie U. Vermeulen. Epidemiological Trends of Diabetes in Alberta: In Alberta Diabetes Atlas 2007: Institute of Health Economics. 2007: p.11-24.

For more information please see:www.achord.ca

ISBN: 978-0-9780024-4-2 (Print)

ISBN: 978-0-9780024-5-9 (Online)

© 2007 Institute of Health Economics

Funded by

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ALBERTA DIABETES ATLAS 2007 �

Table of Contents

Acknowledgements ........................................................................................................................................ iii.

Chapter. 1. Background and Methods........................................................................................................................... 1

Chapter. 2. Epidemiological Trends of Diabetes in Alberta.............................................................................. 11

Chapter. 3. Diabetes and Health Care Utilization in Alberta......................................................................... 25

Chapter. 4. Diabetes and Cardiovascular Disease in Alberta......................................................................... 45

. Acute.Coronary.Syndrome.and.Diabetes............................................................................ 47

. Heart.Failure.and.Diabetes............................................................................................................ 57

. Stroke.and.Diabetes........................................................................................................................... 63

Chapter. 5. Diabetes and Lower Limb Amputations in Alberta.................................................................... 73

Chapter. 6. Diabetes and Kidney Disease in Alberta........................................................................................... 83

Chapter. 7. Diabetes and Eye Disease in Alberta................................................................................................... 95

Chapter. 8. Diabetes and Mental Health Disorders in Alberta......................................................................113

Chapter. 9. Diabetes and First Nations People in Alberta ...............................................................................127

Chapter. 10. Key Findings and Policy Options ...........................................................................................................141

. . Glossary ................................................................................................................................................................147

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ALBERTA DIABETES ATLAS 2007 � � �

ACKNOWLEDGEMENTS

he concept, writing and production of the Alberta Diabetes Atlas 2007 would not have been possible without the direction and support from a large number of individuals. The Alberta Diabetes Surveillance System (ADSS) staff would like to thank the ADSS

Steering Committee, and the ADSS Working Group Members who contributed as authors. We would also like to especially thank the following individuals:

Greg Hugel and Sheri Pohar conducted the data analyses and produced the figures for all chapters in the Alberta Diabetes Atlas 2007.

Alberta Health and Wellness provided us with consistent and valuable data management, and we especially thank Fred Ackah (Health Data Analyst) for his support on this project.

The ADSS logo was inspired by Sydney Lydynuik (age 9, Grade 4, Good Shepherd Catholic Elementary School). We are happy to report that Sydney was proud to present her contribution at her show and tell period at school.

ADSS Staff

Jeffrey.A..Johnson.PhD. Principal Investigator

Stephanie.U..Vermeulen.MSc. Project Manager

Greg.Hugel.MSc. Data Analyst

Sheri.Pohar.PhD. Data Consultant

Sherry.Lydynuik. Administrative Assistant

ADSS Steering Committee Members

Jan.Hux.MD,.SM.Institute.for.Clinical.Evaluative.Sciences.And.University.of.Toronto

Richard.Lewanczuk.MD,.PhD.Division.of.Endocrinology.University.of.Alberta

Sumit.R..Majumdar.MD,.MPH.Division.of.General.Internal.Medicine.University.of.Alberta

Hude.Quan.MD,.PhD.Department.of.Community.Health.Sciences.University.of.Calgary

Larry.W..Svenson.BSc..Public.Health.Surveillance.and.Environmental.Health.Branch.Alberta.Health.and.Wellness

Jeffrey.A..Johnson.PhD.(Chair).School.of.Public.Health.University.of.Alberta

Cheryl.Andres.BN.Director,.Transitional.Care.Chinook.Health

Alun.L..Edwards.MD.Division.of.Endocrinology.University.of.Calgary

Dawn.Friesen.MN.Population.Health.Strategies.Branch.Alberta.Health.and.Wellness

William.A..Ghali.MD,.MPH.Department.of.Medicine.and.Community.Health.Sciences.University.of.Calgary

Brenda.R..Hemmelgarn.PhD,.MD.Division.of.Nephrology.University.of.Calgary

T

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�v ALBERTA DIABETES ATLAS 2007

ADSS Working Group Members

Cynthia.A..Beck.MD,.MASc.Department.of.Psychiatry.University.of.Calgary

Lauren.C..Brown.MSc..School.of.Public.Health.University.of.Alberta

Lynden.Crowshoe.MD.Department.of.Family.Medicine.University.of.Calgary

Alun.L..Edwards.MD.Division.of.Endocrinology.University.of.Calgary

Dean.T..Eurich.PhD.School.of.Public.Health.University.of.Alberta

Brenda.R..Hemmelgarn.PhD,.MD.Division.of.Nephrology.University.of.Calgary

Kailash.K..Jindal.MD.Division.of.Nephrology.University.of.Alberta

Jeffrey.A..Johnson.PhD.School.of.Public.Health.University.of.Alberta

Scott.Klarenbach.MD,.MSc.Division.of.Nephrology.University.of.Alberta

Malcolm.King.PhD.Division.of.Pulmonary.Medicine..University.of.Alberta

Sumit.R..Majumdar.MD,.MPH.Division.of.General.Internal.Medicine.University.of.Alberta

Finlay.A..McAlister.MD,.MSc..Division.of.General.Internal.Medicine.University.of.Alberta

M..Sean.McMurtry.MD,.PhD.Division.of.Cardiology.University.of.Alberta

Colleen.M..Norris.MSc,.PhD.Faculties.of.Nursing.and.Medicine.University.of.Alberta

Hude.Quan.MD,.PhD.Department.of.Community.Health.Sciences.University.of.Calgary

Doreen.M..Rabi.MD,.MSc..Division.of.Endocrinology.University.of.Calgary

Kelli.Ralph-Campbell,.BA..Department.of.Medicine.University.of.Alberta

Christopher.J..Rudnisky.MD,.FRCSC.Department.of.Ophthalmology.University.of.Alberta

Peter.A..Senior.MBBS,.PhD..MRCP(UK).Division.of.Endocrinology.University.of.Alberta

Scot.H..Simpson.BSP,.PharmD,.MSc..Faculty.of.Pharmacy..University.of.Alberta

Larry.W..Svenson.BSc..Public.Health.Surveillance.and.Environmental.Health.Branch.Alberta.Health.and.Wellness

Matthew.T.S..Tennant.BA,.MD,.FRCSC.Department.of.Ophthalmology.University.of.Alberta

Marcello.Tonelli.MD,.SM,.FRCP(C).Division.of.Nephrology.University.of.Alberta

Ross.T..Tsuyuki..BSc(Pharm),.PharmD,.MSc,..Professor.of.Medicine.(Cardiology),.Director,.EPICORE.Centre.University.of.Alberta

Ellen.L..Toth.MD.Department.of.Medicine.University.of.Alberta

Stephanie.U..Vermeulen.MSc..Institute.of.Health.Economics.Edmonton,.Alberta

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ALBERTA DIABETES ATLAS 2007 �

Chapter � Background and Methods

Jeffrey A. Johnson

Stephanie U. Vermeulen

Greg Hugel

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ALBERTA DIABETES ATLAS 2007 �

CHAPTER �

BACKGROUND AND METHODS

The Alberta Diabetes Surveillance System (ADSS) was created in 2006 in a partnership between Alberta Health and Wellness (AHW) and the Institute of Health Economics (IHE). The purpose of the ADSS is to provide information on diabetes in the province of Alberta. This information includes the incidence, prevalence and use of health care services for people with diabetes, along with information about their related comorbidities and complications.

Ongoing surveillance of diabetes through the ADSS will, over time, help to inform health professionals, regional health authorities and Alberta Health and Wellness if efforts to reduce the overall burden of diabetes are effective.

You are reading the first version of the Alberta Diabetes Atlas. It is the first comprehensive document produced in Alberta that contains a broad perspective of the impact that diabetes has on Albertans and on the health care system. To enhance interpretability and usability, this information is summarized at the provincial and health regional level (see Figure 1.1). This Alberta Diabetes Atlas has been distributed to all regional health authorities and diabetes health professionals in the province.

BACKGROUND

Diabetes is a chronic disease affecting more than 5% of Canadians over 20 years of age.(1) It is a serious and growing public health concern in Canada, where healthcare costs of patients with diabetes are projected to be in excess of $6 billion in 2006.(2) Surveillance of diabetes is therefore essential for quantifying the burden of disease and related complications, monitoring resource utilization, developing and evaluating policies and programs, and stimulating research.(3,4)

To that end, the National Diabetes Surveillance System (NDSS) was launched in Canada in 1999 as part of the Canadian Diabetes Strategy. The NDSS currently utilizes existing provincial and territorial administrative health care data to identify diabetes cases.(1,4-6) Prior to the development of the NDSS, estimates of the diabetes burden in Canada were based upon self-reported diabetes in surveys, hospital and mortality data or extrapolated from American figures.(7) Current goals of the NDSS include further development and maintenance of a national, comprehensive, standardized database for diabetes surveillance and provision of population-based diabetes information in order to evaluate health care utilization, policy and process.(1,5) While very valuable, the information available from the NDSS is limited when considering local strategies and policy decisions. Provinces such as Alberta are able to produce substantially richer information in a more timely manner with the broad scope of administrative data.

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� ALBERTA DIABETES ATLAS 2007

CHAPTER �BACKGROUND AND METHODS

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

Much higher that provincial average

Higher than provincial average

Average

Lower than provincial average

Much lower than provincial average

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

Much higher that provincial average

Higher than provincial average

Average

Lower than provincial average

Much lower than provincial average

In May 2003, Alberta Health and Wellness announced the Alberta Diabetes Strategy 2003-2013 with a focus on the primary prevention of type 2 diabetes. Epidemiologic research has shown that key risk factors for type 2 diabetes (e.g., physical inactivity, obesity, and dietary factors) may be changed by focusing on healthy living practices, particularly healthy eating and active living. Consequently, primary prevention is the focus and key to reducing the risk of developing type 2 diabetes. Additionally, Alberta’s Diabetes Strategy also addresses the challenges faced by those who have already been diagnosed with diabetes. Helping those with diabetes to prevent and reduce serious complications is the focus of the secondary and tertiary prevention components of the Alberta Diabetes Strategy.

Figure 1.1 Alberta Health Reg�ons

DIABETES

Diabetes mellitus (DM) is a chronic health condition that is associated with increased morbidity and early mortality. Although there are different types of diabetes, administrative data such as data used for the NDSS and ADSS is presently unable to distinguish between them. It is still important, however, to recognize the different disease processes in order to assess the overall burden.

When someone has diabetes, it means that their body has difficulty making insulin and/or using the insulin that they produce. This is problematic because insulin is required to move glucose into cells so that it can be used by body tissues and organs. When glucose remains in the blood, blood glucose levels can rise to dangerously high levels and result in acute complications. Higher than normal blood glucose levels also can result in long-term organ damage and affect the eyes, kidneys and cardiovascular system.

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CHAPTER �BACKGROUND AND METHODS

ALBERTA DIABETES ATLAS 2007 �

Type 1 diabetes usually occurs early in life during childhood or adolescence. An organ called the pancreas is unable to produce insulin. This is why individuals with type 1 diabetes need to inject insulin several times a day. Type 1 diabetes accounts for 5-10% of all diabetes cases.

Type 2 diabetes is usually associated with onset after 30-40 years of age; however during the past decade, type 2 diabetes has become much more prevalent in younger individuals. This is thought to be associated with lifestyle factors including physical inactivity and obesity. In type 2 diabetes, the pancreas does not produce enough insulin, or the body does not properly use the insulin it makes. Type 2 diabetes accounts for 90-95% of all diabetes cases.

Gestational diabetes occurs only in pregnant women. It is a form of glucose intolerance which usually disappears after six weeks postpartum. There is evidence to suggest that women with gestational diabetes are at a higher risk of developing type 2 diabetes later in life.

Physical activity and a healthy diet are indicated for all individuals with diabetes. As stated above, regular insulin injections are required for people with type 1 diabetes while those who have type 2 diabetes can sometimes be managed with exercise and diet alone. Depending on the severity of the disease, certain people who have type 2 diabetes may also need oral antidiabetic agents (e.g., pills) or even insulin to better control their blood glucose levels.

METHODS

The Alberta Diabetes Atlas is organized into 8 main chapters, each focusing on an important aspect of diabetes in Alberta. Each chapter is organized in the same way. A short background is provided, but the focus of each chapter is on the trends over time, the age-specific rates, and the regional picture of diabetes in Alberta, presented in graphical or map formats. Comments on these trends are provided and key points are highlighted.

Below is a general overview of the methods used in creating this Alberta Diabetes Atlas. Specific methods for each of the different topic areas are highlighted in the respective chapters.

Data SourcesThis Alberta Diabetes Atlas contains data derived from a single source, the administrative databases of Alberta Health and Wellness. Publicly funded health insurance systems routinely generate person-specific administrative data every time a diagnosis is made or a procedure is billed to the provincial governments. From a health surveillance perspective, the ADSS is able to capitalize on this in order to report on the true burden of diabetes in Alberta. These databases contain de-identified information at the personal level on demographics (age, sex, health region, First Nations status), health care utilization (hospitalizations, physician services, ambulatory care), as well as diagnostic and procedure codes. Trends in diabetes and complications over a ten year period, from 1995 to 2005 are reported unless otherwise specified.

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� ALBERTA DIABETES ATLAS 2007

CHAPTER �BACKGROUND AND METHODS

The ADSS reports on diabetes and comorbidities and complications by employing data from the following AHW databases:

1. Discharge Abstract Database (Hospital Morbidity)

2. Alberta Physician Claims Data

3. Ambulatory Care Classification System (includes Emergency Department encounters)

4. Vital Statistics - Mortality

Diabetes Case DefinitionIn order to identify a case of diabetes from the administrative databases, we applied the algorithm used by the NDSS. The current NDSS case definition requires that an individual must have EITHER:

• One hospitalization with an ICD-9 code of 250 (diabetes mellitus), selected from all available diagnostic codes on the Hospital Discharge Abstract for years 1995-2001, or equivalent ICD-10 codes (E10-14) diabetes for years after 2001/2002;

OR

• Two physician claims with an ICD-9 code of 250 (diabetes mellitus) within two years.

The case date is defined as the latest date of hospitalization, or the later of the two physician claims that contribute to the case definition.(1,5) In validation studies, this case definition has been found to have a sensitivity ranging from 69% to 91% when compared with diabetes registries, medical charts, health survey data or drug claim data.(6,8,9)

The current NDSS case definition has been validated in individuals aged 20 years and over. As such, we are only reporting on the adult population in this version of the Alberta Diabetes Atlas. While diabetes in children is increasing, the majority of people with diabetes are still adults. Nonetheless the NDSS is currently developing a strategy to include the population under 20 years of age in the ongoing surveillance of diabetes. Future versions of the Alberta Diabetes Atlas will report on the full population.

One difference to note between the ADSS and the NDSS case definitions is that we chose not to exclude women who may have gestational diabetes, as indicated by codes for pregnancy or obstetric procedures. We included these cases due to the elevated risk of subsequently developing diabetes, thus allowing the ADSS to assess that risk on a population basis in the future.

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CHAPTER �BACKGROUND AND METHODS

ALBERTA DIABETES ATLAS 2007 �

Incidence, Prevalence and Mortality RatesIn order to interpret the results of this Atlas, it is important to understand the terms incidence and prevalence.

Incidence is a measure of new diabetes cases arising within a particular timeframe. Therefore, diabetes incidence is the number or the rate of new cases each year in Alberta. To calculate diabetes incidence, the following formula is used:

Total.#.of.people.with.a.diabetes.incident.date.in.the.current.calendar.year

(Total.population.count.for.current.calendar.year).–.(Prevalent.diabetes.cases).+.(Incident.diabetes.cases)

It is important to subtract the prevalent or existing diabetes cases from the denominator because those who already have diabetes are not at risk of developing it.

Prevalence is the number or rate of diabetes cases existing within a population during a particular time period. Prevalence includes incidence or in other words, existing cases include new cases. For example, if an individual becomes incident one year, they are also considered prevalent in that year and every subsequent year. The following formula is used to calculate diabetes prevalence:

Total.#.of.people.with.diabetes.in.the.current.calendar.year

Total.population.count.for.current.calendar.year

Estimates of incidence, prevalence and total population counts in Alberta are taken from the mid-year Alberta Health and Wellness data. The calculated rates are also reported as age and sex-adjusted to the Alberta population from the 2001 Canadian Census in order to account for differences in population age structure over time, or in different health regions.(10)

The Alberta Diabetes Atlas also reports on mortality in Alberta. The mortality rates among people with and without diabetes are compared in Chapter 2, Epidemiological Trends of Diabetes in Alberta. The ratio between the two rates reflects the significance of diabetes mortality in the population in question. The following formula is used to calculate mortality rate:

Mortality. .. Total.#.of.deaths.among.people.WITH.diabetes.during.the.current.calendar.year(with.diabetes).

=. . Total.#.of.people.WITH.diabetes.during.the.current.calendar.year

Mortality.. . Total.#.of.deaths.among.people.WITHOUT.diabetes.during.the.current.calendar.year(without.diabetes).

=. Total.#.of.people.WITHOUT.diabetes.during.the.current.calendar.year

Mortality.rate.ratio.=. Mortality.rate.among.persons.with.diabetes

. . Mortality.rate.among.persons.without.diabetes

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CHAPTER �BACKGROUND AND METHODS

Health Care Utilization It is intuitive that individuals who are sicker consume more health care resources. This is the case in people with diabetes due to the amount of complications and comorbidities they suffer.(11,12) Use of physician services in the community, and admissions to the emergency department and hospital are reported for people with and without diabetes in this Atlas.

Diabetes Complications and Comorbidities Higher or lower than normal blood glucose levels are associated with acute complications of diabetes that can be life-threatening. Mild lows can be treated by taking some sugar or juice. More severe blood sugar lows or highs may require medication or use of emergency services.

In addition to these acute complications, chronic complications tend to occur over time and are responsible for the majority of the morbidity and mortality for people with diabetes. Chronic complications that can occur are blindness and other forms of eye disease, cardiovascular disease, kidney problems and nerve damage. Furthermore, the impact of chronic medical conditions such as diabetes on mental health is becoming increasingly recognized.

The Alberta Diabetes Atlas contains chapters on these important complications and comorbidities associated with diabetes. For each specific topic, rates will be compared in people with diabetes and people without diabetes. As with the case definition for diabetes itself, case definitions for the specific complications and comorbidities are based on diagnostic or procedure codes contained in the administrative databases. The specific case definitions for these are identified and listed in the Appendix of each relevant chapter.

Diabetes and First NationsThe epidemiology of diabetes in the First Nations population is considerably different from the non-First Nations population in Canada.(13) In addition, mortality rates and diabetes complications are more common among First Nations people than non-First Nations people. The ongoing surveillance of diabetes in First Nations people is an important part of the ADSS. In this version of the Alberta Diabetes Atlas, we report on the incidence, prevalence, age-specific and regional trends of First Nations and non-First Nations for those with and without diabetes.

SUMMARY

Clearly, diabetes is a significant and contemporary health concern that will continue to have an increasing impact on provincial and federal health care systems and on the health of all Canadians. The Alberta Diabetes Surveillance System is a key component of the Alberta Diabetes Strategy, which is aimed at reducing the burden of diabetes for Albertans. This Alberta Diabetes Atlas provides a broad perspective of the burden that diabetes has on Alberta.

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CHAPTER �BACKGROUND AND METHODS

ALBERTA DIABETES ATLAS 2007 �

References 1. Health Canada. 2nd Report on the National Diabetes Surveillance System. 2007. Ottawa, Health Canada.

2. Ohinmaa A, Jacobs P, Simpson SH, Johnson JA: The projection of prevalence and cost of diabetes in Canada: 2000 to 2016. Canadian Journal of Diabetes 28:116-23, 2004

3. Safran MA, Vinicor F: The war against diabetes. How will we know if we are winning? Diabetes Care 22:508-516, 1999

4. Saydah SH, Geiss LS, Tierney E, Benjamin SM, Engelgau M, Brancati F: Review of the performance of methods to identify diabetes cases among vital statistics, administrative, and survey data. Ann Epidemiol 14:507-516, 2004

5. Health Canada. Responding to the challenge of diabetes in Canada. First report of the National Diabetes Surveillance System (NDSS). 2003. Ottawa, Health Canada.

6. Hux JE, Ivis F, Flintoft V, Bica A: Diabetes in Ontario: determination of prevalence and incidence using a validated administrative data algorithm. Diabetes Care 25:512-516, 2002

7. Clottey C, Mo F, LeBrun B, Mickelson P, Niles J, Robbins G: The development of the National Diabetes Surveillance System (NDSS) in Canada. Chronic Dis Can 22:67-69, 2001

8. LeBlanc, J. and Kephart, G. Assessment of the sensitivity and specificity of Nova Scotia administrative databases for detecting diabetes mellitus. Report to NDSS Validation Working Group. 1998. Halifax, Population Health Research Unit.

9. Van Til, L. Report to NDSS Validation Working Group. 2001. Charlottetown, Document Publishing Center.

10. Statistics Canada: Age and Sex for Population, for Canada, Provinces, Territories, Census Metropolitan Areas and Census Agglomerations, 2001 Census. [article online], 2007. Accessed Catalog Number: 95F0300XCB2001004

11. Hux JE, Booth GL, Slaughter PM, Laupacis A (eds). Diabetes in Ontario: An ICES Practice Atlas: Institute for Clinical Evaluative Sciences, 2003.

12. Simpson SH, Corabian P, Jacobs P, Johnson JA: The cost of major comorbidity in people with diabetes mellitus. CMAJ 168:1661-1667, 2003

13. First Nations Information Governance Committee by the First Nations Centre at the National Aboriginal Health Organization. First Nations and Inuit Regional Health Surveys, 1997; A Synthesis of the National and Regional Reports. 2004. 10-11-2006.

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ALBERTA DIABETES ATLAS 2007 ��

Chapter � Ep�dem�olog�cal Trends of D�abetes �n Alberta

Jeffrey A. Johnson

Stephanie U. Vermeulen

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ALBERTA DIABETES ATLAS 2007 ��

CHAPTER �

EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

KEY MESSAGES

• Diabetes is a large and growing health problem for Albertans.

• There are 130,000 adults living with diabetes in Alberta, which is a doubling of the number ten years ago.

• There were about 12,000 new cases of diabetes identified in Alberta in 2004.

• People with diabetes are more than twice as likely to die each year, compared to people without diabetes.

• Diabetes is most prevalent in the aging population, who tend to have additional health problems that subsequently increase the burden on our health care system.

• Northern Lights Health Region has the highest age-adjusted prevalence of diabetes in Alberta at 6.8%, while the provincial average is 5.3%. This region also has the highest diabetes incidence in Alberta.

BACKGROUND

According to the National Diabetes Surveillance System (NDSS), the prevalence of diabetes among adult Canadians in 1999/2000 was 5.1%.(1) This means that in 1999/2000, there were over 2 million adult Canadians living with diabetes. Canadian adults with diabetes are twice as likely to die prematurely than people without diabetes. These figures are staggering and as we report here, these trends are all too similar while observing the story of diabetes in Alberta.

This chapter will examine incidence, prevalence and mortality of those with diabetes in Alberta over the past decade, 1995 to 2005. Results will be presented as crude rates, that is, the actual counts and rates on a population basis, as well as age-adjusted rates for the purpose of comparison. Rates will also be presented by health region in order to establish a geographic representation of diabetes across Alberta. These general epidemiological trends of diabetes serve as a starting point when trying to assess the burden of diabetes in Alberta.

METHODS

In order to interpret the results of this report it is important to understand the terms incidence and prevalence. These concepts along with their formulas are covered in more depth in the Background and Methods Chapter of this Atlas.

Incidence is a measure of new cases arising within a particular timeframe. Therefore, diabetes incidence is the number of new cases in Alberta. The incidence rate is the number of new cases of diabetes relative to the total population at risk in each calendar year.

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

6

5

4

3

2

1

0

Female

Male

Total

68,56271,735

78,94184,624

90,64497,600

105,176112,287

120,465

129,184

75,090

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

140,000

120,000

100,000

80,000

60,000

40,000

20,000

0

Female

Male

Total

Year

Rat

e pe

r 10

0

Year

Num

ber

of C

ases

2-1

2-2

Prevalence is the number of cases existing within a population at any point in time. Diabetes prevalence includes new and existing cases in Alberta for each calendar year. For example, if an individual becomes incident one year, they are also considered prevalent in that year and every subsequent year.

In the current Alberta Diabetes Atlas, we estimated diabetes incidence and prevalence rates based on the total population counts for Albertans registered with Alberta Health and Wellness as of June 30 in each year.

The calculated rates are also reported as age-adjusted in order to account for differences in population age structure, or differences in health regions overtime. We used a method of direct standardization(2), using the 2001 Canadian Census for Alberta as the reference population.(3)

Mortality is reported as the proportion of people who died each year, and is compared between people with and without diabetes.

PREVALENCE

Figure 2.1 Prevalent D�abetes Cases, ����-�00�

Nearly 130,000 adults are living with diabetes in Alberta in 2005, a figure that’s almost doubled over the last ten years (Figure 2.1). Diabetes was slightly more prevalent in females up to about 2001 until it became slightly more prevalent in males.

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CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

6

5

4

3

2

1

0

Female

Male

Total

68,56271,735

78,94184,624

90,64497,600

105,176112,287

120,465

129,184

75,090

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

140,000

120,000

100,000

80,000

60,000

40,000

20,000

0

Female

Male

Total

Year

Rat

e pe

r 10

0

Year

Num

ber

of C

ases

2-1

2-2

10000

9000

8000

7000

6000

5000

4000

3000

2000

1000

0

300000

250000

200000

150000

100000

50000

0

Age Group (Years)

Female

Male

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

25

20

15

10

5

0

Age Group (Years)20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Female

Male

Total

Rat

e pe

r 10

0

Tot

al P

opul

atio

n D

istr

ibut

ion

Num

ber

of C

ases

2-3

2-4

Figure 2.2 Age-Adjusted D�abetes Prevalence Rates, ����-�00�

The prevalence of diabetes has been steadily increasing in both males and females over the past decade. In 2005, the unadjusted prevalence of diabetes in Alberta adults was 5.5%. Adult males experience a slightly higher prevalence than females. Over the 1995 to 2005 period, the male age-adjusted rate increased by 43.9% overall, while the female rate increased by 37.6% (Figure 2.2).

Figure 2.3 Age D�str�but�on of Prevalent D�abetes Cases, �00�

Due to the chronic nature of diabetes the number of cases increases as people become older, peaking in age group 55-59 (Figure 2.3). When people with diabetes become older than 59 years, the prevalence remains high, but begins to decrease, presumably as people die.

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

10000

9000

8000

7000

6000

5000

4000

3000

2000

1000

0

300000

250000

200000

150000

100000

50000

0

Age Group (Years)

Female

Male

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

25

20

15

10

5

0

Age Group (Years)20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Female

Male

Total

Rat

e pe

r 10

0

Tot

al P

opul

atio

n D

istr

ibut

ion

Num

ber

of C

ases

2-3

2-4

Male cases outnumber female cases beginning in age group 50-54 years until age group 75-79. From age groups 80 and older, diabetes is more prevalent in females cases, perhaps due to women having longer life expectancies. Female cases also have a much higher prevalence of diabetes in the younger ages until about ages 40-44. This is due, in part, to the risk of gestational diabetes during women’s childbearing years. Women who develop gestational diabetes are at increased risk of subsequently developing type 2 diabetes.(4)

Figure 2.4 Age-Spec�fic D�abetes Prevalence Rates, �00�

Diabetes prevalence rates increases with age in both sexes, rising considerably after ages 45-49 (Figure 2.4). Prevalence rates peak in the 75-79 age group, approaching 16% in females and 19% in males. This is a substantial increase over the 20-29 age group, where prevalence is less than 1%. Diabetes prevalence in females is slightly higher than in males, until about age 50, when prevalence in males becomes higher.

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CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

Female

Male

Total

Female

Male

Total

9

8

7

6

5

4

3

2

1

0

14,000

12,000

10,000

8,000

6,000

4,000

2,000

0

Rat

e pe

r 10

0

2.5

2.7 6,064 6,082 6,2577,017

8,389

9,169

10,14210,848 10,563

11,927

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004Year

Num

ber

of C

ases

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

Much higher that provincial average

Higher than provincial average

Average

Lower than provincial average

Much lower than provincial average

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

Much higher that provincial average

Higher than provincial average

Average

Lower than provincial average

Much lower than provincial average

The age-adjusted prevalence of diabetes varies across the province. The highest rates are in the Northern Lights region at 6.8%, and the lowest rates in the Calgary region at 4.7% (Figure 2.5 and 2.6). The average provincial age-adjusted prevalence rate is 5.3%. Calgary, David Thompson and East Central all have an age-adjusted prevalence rate below the provincial average while Chinook, Palliser, Capital, Aspen, Peace Country and Northern Lights have rates above.

Diabetes prevalence rates are generally higher in males except for the three most northern regions of Aspen, Peace Country and Northern Lights where rates are higher in females.

Figure 2.5 Age-Adjusted D�abetes Prevalence Rates by Reg�on, �00�

Figure 2.6 Age-Adjusted D�abetes Prevalence Rates by Reg�on, �00�

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

Female

Male

Total

Female

Male

Total

9

8

7

6

5

4

3

2

1

0

14,000

12,000

10,000

8,000

6,000

4,000

2,000

0

Rat

e pe

r 10

0

2.5

2.7 6,064 6,082 6,2577,017

8,389

9,169

10,14210,848 10,563

11,927

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004Year

Num

ber

of C

ases

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Prevalence differences among Alberta’s health regions should be interpreted with caution due to the effects of different populations and access to care issues. For example, diabetes prevalence in First Nations people is higher than for non-First Nations people, and there are a larger proportion of First Nations people living in Northern Alberta and Southern Alberta. This may in part explain why the highest rates of diabetes are in Northern and Southern Alberta. This concept will be further discussed in the First Nations chapter of the Atlas.

As well, access to care is believed to be limited in rural Alberta, and because the ADSS is not able to capture sub-clinical cases which are undetected or undiagnosed, only diagnosed cases are reported in incidence and prevalence estimates.

INCIDENCE

During the time period 1995-2004, there were more than 86,000 new cases of diabetes identified in Alberta (Figure 2.7). The number of diabetes cases identified in 2004 (n=11,927) was almost double that of the new cases identified in 1995 (n=6064).

Figure 2.7 Inc�dent D�abetes Cases, ����-�00�

After adjusting for age, the incidence of diabetes appears to be increasing steadily over the past decade, with more new cases being diagnosed in males compared to females across the years (Figure 2.8).

Page 25: ALBERTA DIABETE S ATLA S 2007

CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

Female

Male

Total

7

6

5

4

3

2

1

0

Female

Male

Total

2.8

2.10

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004Year

Rat

e pe

r 10

00

0

2

4

6

8

10

12

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Rat

e pe

r 10

00

Females with DiabetesMales with DiabetesFemales without DiabetesMales without Diabetes

Deaths with DiabetesDeaths without Diabetes

20

18

16

14

12

10

8

6

4

2

0

25

20

15

10

5

0

25

20

15

10

5

0

Age Group (Years)

Year

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Female

Male

2.9

2.12

2.13

Cas

es p

er 1

000

Rat

e pe

r 10

00

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+Age Group (Years)

Rat

e pe

r 10

0

8

7

6

5

4

3

2

1

0

Rat

e R

atio

(D

iabe

tes:

No

Dia

bete

s)

Figure 2.8 Age-Adjusted D�abetes Inc�dence Rates, ����-�00�

Diabetes incidence increases with age until 70-74 years in males and 75-79 years in females, after which it decreases (Figure 2.9). Women aged 20-34 years have a greater proportion of incident cases than men. Gestational diabetes cases in a woman’s childbearing years likely accounts for this increase in incidence cases among women compared to men in these ages. However, males have increased diabetes incidence compared to females across all ages beginning at 35-39 years until 85+ years.

Figure 2.9 Age-Spec�fic D�abetes Inc�dence Rates, �00�

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�0 ALBERTA DIABETES ATLAS 2007

CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

Female

Male

Total

7

6

5

4

3

2

1

0

Female

Male

Total

2.8

2.10

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004Year

Rat

e pe

r 10

00

0

2

4

6

8

10

12

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Rat

e pe

r 10

00

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

Much higher that provincial average

Higher than provincial average

Average

Lower than provincial average

Much lower than provincial average

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

Much higher that provincial average

Higher than provincial average

Average

Lower than provincial average

Much lower than provincial average

As with prevalence, age-adjusted diabetes incidence varies across the province (Figure 2.10 and 2.11). In 2004, the highest incidence rates were in the Northern Lights region at 7.5 new diabetes cases per 1000 people. The lowest rates were in East Central with 5 cases per 1000. As a point of reference, the average provincial age-adjusted incidence rate is 5.5 cases per 1000. Males have a greater proportion of diabetes incidence than females across all regions in Alberta.

Figure 2.10 Age-Adjusted D�abetes Inc�dence Rates by Reg�on, �00�

Figure 2.11 Age-Adjusted D�abetes Inc�dence Rates by Reg�on, �00�

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CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

Females with DiabetesMales with DiabetesFemales without DiabetesMales without Diabetes

Deaths with DiabetesDeaths without Diabetes

20

18

16

14

12

10

8

6

4

2

0

25

20

15

10

5

0

25

20

15

10

5

0

Age Group (Years)

Year

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Female

Male

2.9

2.12

2.13

Cas

es p

er 1

000

Rat

e pe

r 10

00

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+Age Group (Years)

Rat

e pe

r 10

0

8

7

6

5

4

3

2

1

0

Rat

e R

atio

(D

iabe

tes:

No

Dia

bete

s)

MORTALITY

The mortality rates among people with diabetes are higher than the mortality rates among people without diabetes. The ratio between the two rates reflects the significance of diabetes on overall mortality.

Figure 2.12 Age-Adjusted Mortal�ty Rates, ����-�00�

While mortality rates for both sexes have decreased over the years, perhaps due in part to the general population’s life expectancy increasing, it is apparent that those who have diabetes have much higher mortality rates than those without diabetes, regardless of sex (Figure 2.12). In the past decade, the overall mortality rates have consistently been over twice as high in the diabetic population compared to those without diabetes.

Men have higher mortality rates than women through the years, but having diabetes amplifies this difference. While diabetic men have higher mortality rates than women with diabetes, the difference appears to have lessened in recent years.

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CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

Females with DiabetesMales with DiabetesFemales without DiabetesMales without Diabetes

Deaths with DiabetesDeaths without Diabetes

20

18

16

14

12

10

8

6

4

2

0

25

20

15

10

5

0

25

20

15

10

5

0

Age Group (Years)

Year

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Female

Male

2.9

2.12

2.13

Cas

es p

er 1

000

Rat

e pe

r 10

001995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+Age Group (Years)

Rat

e pe

r 10

0

8

7

6

5

4

3

2

1

0

Rat

e R

atio

(D

iabe

tes:

No

Dia

bete

s)

Figure 2.13 Age-Spec�fic Mortal�ty Rates, �00�

Mortality rates for those who have diabetes are consistently higher at all ages than mortality rates for those who do not have diabetes (Figure 2.13). Both individuals with and without diabetes have higher mortality rates as they become older. The mortality rate ratio demonstrates that younger people with diabetes have a much higher risk of dying compared to older individuals who have diabetes. In fact, individuals between the ages of 30-34 years are 6.7 times more likely to die if they have diabetes whereas, people 65 years or older are less than 2 times more likely to die if they have diabetes. This reduction in the relative risk of death is likely due to competing causes of death in the older ages.

DISCUSSION

The observed trends for the number of Albertans living with diabetes follow similar trends for the rest of Canada(1), the US(5), and the rest of the world.(6,7) This confirms that diabetes is a large and growing health problem.

Of particular note is the doubling in the number of people living with diabetes in Alberta over the past decade. The prevalence of diabetes is increasing because of the growing numbers of new cases each year, and because those who have diabetes are living longer. While people with diabetes are still 2 to 4 times more likely to die than people without diabetes, the mortality rates over the past decade have declined, which is encouraging. This trend is likely due to fewer heart attacks and strokes for people with diabetes, which has also been seen in other parts of Canada.(8) The troubling news is that while the heart attack and stroke rates have declined, the actual number of heart attacks and strokes are increasing as the number of people with diabetes grows.

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CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

While the information presented in the Alberta Diabetes Atlas provides a valuable representation of the burden of diabetes in our province, we recognize that there are several important limitations in using the administrative data from Alberta Health and Wellness. We have used a case definition to identify people with diabetes that requires individuals to have been diagnosed with diabetes by a physician, or be admitted to hospital. It is well recognized that many people who have diabetes are not yet diagnosed.(9,10) Further, there are likely some individuals who have been diagnosed with diabetes and are relatively healthy who have not seen a physician frequently enough to qualify as a diabetes case under the current definition. Because of these limitations, it is regarded that the ADSS, our surveillance system, generally underestimates the true burden of diabetes on a population basis.

Nonetheless, in applying the case definition in a consistent way across the time period, we can be confident that we are observing the true trends of the epidemiology of diabetes in Alberta. Surveillance systems such as the ADSS are intended to provide a broad, population-based perspective. That said, these first impressions may guide further detailed surveillance where data anomalies or interesting patterns can be explored in greater detail.

For example, gestational diabetes is a special form of diabetes which is included in the ADSS case definition. The NDSS excludes cases of gestational diabetes,(1) hence the prevalence and incidence of diabetes in younger female Albertans may appear higher than national estimates. We chose to include women with gestational diabetes as they have an increased risk of subsequently developing type 2 diabetes later in life.(4) Furthermore, gestational diabetes also puts the newborn infant at increased health risks.(4) By including women with gestational diabetes in this first version of the Alberta Diabetes Atlas, we will be able to monitor their future health status, including the health of their offspring.

Presenting the number of cases with diabetes over the past decade also provides us with a hint of what we can expect for the future. Without tremendous effort by our social and public health care systems, it is entirely likely that the upward trends in both incidence and prevalence of diabetes will continue for the next decade. Like the rest of Canada and the world, the prevalence of diabetes in Alberta could more than double again in the next 5 to 6 years.

CONCLUSION

Information such as the trends presented here should be viewed as a call to action. Provincial and regional decision-makers will find this information useful in the consideration and evaluation of efforts to curb the burden of diabetes. Information available in future versions of the Alberta Diabetes Atlas will tell us how well we are doing in achieving that goal.

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CHAPTER �EPIDEMIOLOGICAL TRENDS OF DIABETES IN ALBERTA

References 1. Health Canada. 2nd Report on the National Diabetes Surveillance System. 2007. Ottawa, Health Canada.

2. Hennekens CH, Buring JE: Epidemiology in Medicine. Philadelphia, Lippincott Williams & Wilkins, 1987

3. Statistics Canada: Age and Sex for Population, for Canada, Provinces, Territories, Census Metropolitan Areas and Census Agglomerations, 2001 Census. [article online], 2007. Accessed Catalog Number: 95F0300XCB2001004

4. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee, Canadian Diabetes Association: Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. Canadian Journal of Diabetes 27:S99-S105, 2003

5. Mokdad AH, Ford ES, Bowman BA, Dietz WH, Vinicor F, Bales VS, Marks JS: Prevalence of obesity, diabetes, and obesity-related health risk factors, 2001. JAMA 289:76-79, 2003

6. Shaw JE, Zimmet PZ, McCarty D, de Court: Type 2 diabetes worldwide according to the new classification and criteria. Diabetes Care 23 Suppl 2:B5-10, 2000

7. Zimmet P, Alberti KG, Shaw J: Global and societal implications of the diabetes epidemic. Nature 414:782-787, 2001

8. Booth GL, Kapral MK, Fung K, Tu JV: Recent trends in cardiovascular complications among men and women with and without diabetes. Diabetes Care 29:32-37, 2006

9. Harris MI, Flegal KM, Cowie CC, Eberhardt MS, Goldstein DE, Little RR, Wiedmeyer HM, Byrd-Holt DD: Prevalence of diabetes, impaired fasting glucose, and impaired glucose tolerance in U.S. adults. The Third National Health and Nutrition Examination Survey, 1988-1994. Diabetes Care 21:518-524, 1998

10. Rathmann W, Haastert B, Icks A, Lowel H, Meisinger C, Holle R, Giani G: High prevalence of undiagnosed diabetes mellitus in Southern Germany: target populations for efficient screening. The KORA survey 2000. Diabetologia 46:182-189, 2003

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ALBERTA DIABETES ATLAS 2007 ��

Chapter � D�abetes and Health Care Ut�l�zat�on �n Alberta

Jeffrey A. Johnson

Doreen M. Rabi

Alun L. Edwards

Stephanie U. Vermeulen

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�� ALBERTA DIABETES ATLAS 2007

Page 33: ALBERTA DIABETE S ATLA S 2007

ALBERTA DIABETES ATLAS 2007 ��

CHAPTER �

DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

KEY MESSAGES

• People with diabetes see GPs almost twice as often and Specialists three times more often than people without diabetes.

• Over the past decade, there has been a steady increase in the number of total physician visits for people with diabetes, with the number of GP visits doubling over the past 10 years.

• There is considerable variation in the use of different services across health regions in Alberta. There are more emergency department visits for people with diabetes living in non-metro health regions compared to metro health regions.

• While there has been an increase in the total number of visits to the emergency department for people with diabetes, the rate of visits for cardiovascular disease has actually declined in recent years.

• People with diabetes spend 2.5 times more days in hospital each year than people without diabetes.

• People with diabetes are 2 to 4 times more likely to be hospitalized for cardiovascular or kidney disease, and over 16 times more likely for lower limb amputations.

BACKGROUND

The societal impact of diabetes mellitus (DM) can be captured in many ways. Information on the prevalence, incidence, morbidity and mortality all help to capture the social burden of diabetes. Another important aspect is the excess health care utilization and costs of care for people with diabetes compared to people without diabetes.(1,2) Management of chronic medical conditions such as diabetes can place tremendous strains on our already burdened health care systems. As each unit of health care service is consumed, there is a price that goes with that service unit; for example, a visit to a general practitioner (GP), specialist physician, emergency department (ED) or a day in the hospital, leading to the total overall cost of these services. This chapter provides a picture of the level of health care utilization for people with diabetes in Alberta.

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CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

Access to appropriate care contributes to better quality of care and better outcomes for people with DM. Health professional organizations and policy-makers have raised concerns about potential shortages of many health professionals; for example, the Canadian Diabetes Association (CDA) guidelines recommend a multidisciplinary team approach to DM care,(3) yet such resources may not always be in place. Furthermore, variations in utilization of health services may indicate inequities in access to care, or may identify different models of care or combinations of care providers being used in different communities. Therefore, this chapter provides an overview of the utilization of physicians, EDs as well as other hospital services for people with and without diabetes. Information such as this can help policy-makers to estimate future requirements for health human resources.

METHODS

Data from Alberta Health and Wellness administrative databases were utilized for these analyses. People with DM were identified within the Alberta Health and Wellness databases by applying the NDSS algorithm (see Methods chapter). All adult patients aged 20 or greater were included in these analyses. From these data, rates of health care utilization for those with and without diabetes were calculated. For each group, the number of people with each specific health care encounter (numerator) was divided by the total number of people in the province or region (denominator), respectively. As with other rates in the Atlas, we used a direct standardization to age and sex adjust rates of health care utilization, using the Alberta population from the 2001 Canadian Census. We present trends of health care utilization over time (1995 to 2005 unless otherwise specified), and across age groups and health regions for the most recent year (2005).

Physician VisitsData were obtained from the Physician Claims database, which captures Alberta resident demographic information for all physician visits and procedures completed in an inpatient or outpatient environment. We identified physician visits to GP and specialists. For visits to specialists, we included cardiologists, endocrinologists, internists, nephrologists, ophthalmologists and psychiatrists, as these were specialties most relevant to the comorbidities included in this version of the Alberta Diabetes Atlas.

Emergency Department VisitsData were obtained from the Ambulatory Care Classification System (ACCS) database, which was established in 1998, and captures information on the nature of encounters with emergency departments in Alberta. We present rates for total ED visits, as well as those specifically associated with cardiovascular disease and glycemic emergencies (see Appendix for specific diagnostic codes included). Glycemic emergencies included comas due to hyper- and hypoglycemia and diabetic ketoacidosis. Because people may have repeated ED visits, we calculated the average number of total ED visits and the proportion of the population with one or more visit for CVD or glycemic emergency.

Page 35: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

DiabetesNo Diabetes

677 690738

792873

9441,014

1,0621,123

1,2681,351

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

1,600

1,400

1,200

1,000

800

600

400

200

0

Female

Male

Total

Year

Vis

its p

er 1

0003.2

10

9

8

7

6

5

4

3

2

1

0

3.1

Ave

rage

Num

ber

of V

isits

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

HospitalizationsData for use of hospital services were obtained from the Discharge Abstracts Database (DAD), which records information including dates, diagnoses and procedures on all admissions to any of the 128 acute care facilities in Alberta. Because people may have repeated hospitalizations, we calculated the average number of total hospital days per year for Albertans, and compared this average for people with and without diabetes. For those with hospitalizations in 2005, we also compared the reason for hospitalization for selected conditions known to be associated with diabetes (see Appendix), using the most responsible diagnostic codes from the DAD. We present these as ratios for people with diabetes compared to people without diabetes to give an indication of the excess burden diabetes places on the hospital system.

FINDINGS

General Practitioner VisitsFrom 1995 to 2005, the average number of GP visits remained fairly stable. People with diabetes had about 75% more GP visits per year compared to people without diabetes (Figure 3.1). For example, in 2005, people with diabetes had about 9 GP visits, while people without diabetes had about 5 GP visits. While the average number of GP visits remained stable, the total number of GP visits for people with diabetes doubled over the past decade, growing from nearly 680,000 visits in 1995, to over 1.35 million in 2005 (Figure 3.2). The excess number of GP visits was common across all age groups (Figure 3.3). People with diabetes were more likely to see a GP in all health regions, although the number of GP visits for people with diabetes was slightly lower for Calgary and Capital than the provincial average, and slightly higher for Palliser and Aspen (Figure 3.4).

Figure 3.1 Age and Sex-Adjusted General Pract�t�oner V�s�ts, ����-�00�

Page 36: ALBERTA DIABETE S ATLA S 2007

�0 ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

DiabetesNo Diabetes

677 690738

792873

9441,014

1,0621,123

1,2681,351

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

1,600

1,400

1,200

1,000

800

600

400

200

0

Female

Male

Total

Year

Vis

its p

er 1

0003.2

10

9

8

7

6

5

4

3

2

1

0

3.1

Ave

rage

Num

ber

of V

isits

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

25

20

15

10

5

0

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

Age Group (Years)

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Rat

io( D

iabe

tes:

No

Dia

bete

s)

Ave

rage

Num

ber

of V

isits

3.3

Ave

rage

Num

ber

of V

isits

12

10

8

6

4

2

0

3.4

Diabetes

No Diabetes

Diabetes

No Diabetes

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes Provincial Average = 8.7

Figure 3.2 Total Number of General Pract�t�oner V�s�ts for People w�th D�abetes, ����-�00�

Figure 3.3 General Pract�t�oner V�s�ts by Age, �00�

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CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

25

20

15

10

5

0

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

Age Group (Years)

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Rat

io( D

iabe

tes:

No

Dia

bete

s)

Ave

rage

Num

ber

of V

isits

3.3

Ave

rage

Num

ber

of V

isits

12

10

8

6

4

2

0

3.4

Diabetes

No Diabetes

Diabetes

No Diabetes

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes Provincial Average = 8.7

Figure 3.4 Age and Sex-Adjusted General Pract�t�oner V�s�ts by Reg�on, �00�

Specialists VisitsThe average number of visits to medical specialists has remained fairly stable over the last 5 years of observation, after an increase in visits from 1995 to 2000 (Figure 3.5). People with diabetes have generally seen specialist physicians 3 times more often than people without diabetes. As with GP visits, while the average number of specialist visits has remained stable, the total number of visits to specialists has increased, more than doubling in the past decade (Figure 3.6). The likelihood of seeing a specialist physician is much higher for people with diabetes in younger adulthood, presumably due to the increased likelihood for all older adults to see specialists (Figure 3.7). In 2005, there was considerable regional variation in the likelihood of seeing a specialist physician. People with diabetes living in Calgary or Capital were much more likely to see a specialist than people living in northern or more rural regions, with the exception of Palliser (Figure 3.8).

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

DiabetesNo Diabetes

5

4

3

2

1

0

3.5

Ave

rage

Num

ber

of V

isits

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

600

500

400

300

200

100

0

Female

Male

Total

244261

282309

343

389412

442

478510

549

Year

Vis

its p

er 1

000

3.6

DiabetesNo Diabetes

5

4

3

2

1

0

3.5

Ave

rage

Num

ber

of V

isits

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

600

500

400

300

200

100

0

Female

Male

Total

244261

282309

343

389412

442

478510

549

Year

Vis

its p

er 1

000

3.6

Figure 3.5 Age and Sex-Adjusted Spec�al�st V�s�ts, ����-�00�

Figure 3.6 Total Number of Spec�al�st V�s�ts for people w�th D�abetes, ����-�00�

Page 39: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

6

5

4

3

2

1

0

16

14

12

10

8

6

4

2

0

Age Group (Years)

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Rat

io( D

iabe

tes:

No

Dia

bete

s)

Ave

rage

Num

ber

of V

isits

3.7

No Diabetes

Diabetes

Ratio (Diabetes: No Diabetes)

Diabetes

No Diabetes

Diabetes

No Diabetes

Ave

rage

Num

ber

of V

isits

6

5

4

3

2

1

0

3.8

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes Provincial Average = 3.5

6

5

4

3

2

1

0

16

14

12

10

8

6

4

2

0

Age Group (Years)

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Rat

io( D

iabe

tes:

No

Dia

bete

s)

Ave

rage

Num

ber

of V

isits

3.7

No Diabetes

Diabetes

Ratio (Diabetes: No Diabetes)

Diabetes

No Diabetes

Diabetes

No Diabetes

Ave

rage

Num

ber

of V

isits

6

5

4

3

2

1

0

3.8

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes Provincial Average = 3.5

Figure 3.7 Age-Spec�fic Rate of Spec�al�st V�s�ts, �00�

Figure 3.8 Age and Sex-Adjusted Spec�al�st V�s�ts by Reg�on, �00�

Page 40: ALBERTA DIABETE S ATLA S 2007

�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

Female

Male

Total

79,571

89,24595,562

101,496107,424

117,029121,356

128,213140

120

100

80

60

40

20

01998 1999 2000 2001 2002 2003 2004 2005

Year

Vis

its p

er 1

000

3.9

3.10

DiabetesNo Diabetes

1998 1999 2000 2001 2002 2003 2004 2005Year

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

Ave

rage

Num

ber

of V

isits

Emergency Department VisitsAs with visits to physicians, the average number of all encounters with the ED has remained stable over the past 8 years for people with and without diabetes (Figure 3.9). People with diabetes were more than twice as likely to visit the ED, and the total number of ED visits for people with diabetes has increased dramatically (Figure 3.10). We observed an interesting U-shaped curve for age-specific rates of ED visits overall, with the likelihood of ED visits for people with diabetes compared to the non-diabetes population being highest for younger adults (Figure 3.11). In contrast to regional differences in physician visits, the likelihood of an ED visit is much higher for the non-metro regions (Figure 3.12). For example, people with diabetes living in Peace Country are more than 4 times as likely to visit an ED than people in Calgary.

When considering the reasons for ED visits, it appears that cardiovascular (CVD) emergencies have become less frequent over the last few years, although people with diabetes are still at twice the risk as people without diabetes (Figure 3.13). Glycemic emergencies, including diabetic coma (as a result of hyper or hypo-glycemia) and diabetic ketoacidosis, showed a slight increase in frequency among the diabetes population the last few years of observation (Figure 3.14).

Figure 3.9 Age and Sex-Adjusted Emergency Department V�s�ts, ����-�00�

Page 41: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

Female

Male

Total

79,571

89,24595,562

101,496107,424

117,029121,356

128,213140

120

100

80

60

40

20

01998 1999 2000 2001 2002 2003 2004 2005

Year

Vis

its p

er 1

000

3.9

3.10

DiabetesNo Diabetes

1998 1999 2000 2001 2002 2003 2004 2005Year

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

Ave

rage

Num

ber

of V

isits

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

3.0

2.5

2.0

1.5

1.0

0.5

0

Age Group (Years)

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Rat

io( D

iabe

tes:

No

Dia

bete

s)

Ave

rage

Num

ber

of V

isits

3.11

Diabetes

No Diabetes

Diabetes

No Diabetes

Ave

rage

Num

ber

of V

isits

3.0

2.5

2.0

1.5

1.0

0.5

0

3.12

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes Provincial Average = 1.0

Figure 3.10 Total Number of Emergency Department V�s�ts, ����-�00�

Figure 3.11 Age-Spec�fic Rates of Emergency Department V�s�ts, �00�

Page 42: ALBERTA DIABETE S ATLA S 2007

�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

3.0

2.5

2.0

1.5

1.0

0.5

0

Age Group (Years)

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Rat

io( D

iabe

tes:

No

Dia

bete

s)

Ave

rage

Num

ber

of V

isits

3.11

Diabetes

No Diabetes

Diabetes

No Diabetes

Ave

rage

Num

ber

of V

isits

3.0

2.5

2.0

1.5

1.0

0.5

0

3.12

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes Provincial Average = 1.0

DiabetesNo Diabetes

1998 1999 2000 2001 2002 2003 2004 2005Year

1998 1999 2000 2001 2002 2003 2004 2005Year

3.13

Perc

ent

with

One

or

Mor

e V

isit

3.14

1.2%

1.0%

0.8%

0.6%

0.4%

0.2%

0%

Perc

ent

with

One

or

Mor

e V

isit

4.5%

4.0%

3.5%

3.0%

2.5%

2.0%

1.5%

1.0%

0.5%

0%

Figure 3.12 Age and Sex-Adjusted Emergency Department V�s�ts by Reg�on, �00�

Figure 3.13 Age and Sex-Adjusted Emergency Department V�s�ts for Card�ovascular D�sease, ����-�00�

Page 43: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

DiabetesNo Diabetes

1998 1999 2000 2001 2002 2003 2004 2005Year

1998 1999 2000 2001 2002 2003 2004 2005Year

3.13

Perc

ent

with

One

or

Mor

e V

isit

3.14

1.2%

1.0%

0.8%

0.6%

0.4%

0.2%

0%

Perc

ent

with

One

or

Mor

e V

isit

4.5%

4.0%

3.5%

3.0%

2.5%

2.0%

1.5%

1.0%

0.5%

0%

Figure 3.14 Age and Sex-Adjusted Emergency Department V�s�ts for Glycem�c Emergenc�es (D�abetes Populat�on only), ����-�00�

HospitalizationsLike other health care services, the average number of days in hospital for Albertans has remained fairly steady over the past decade; however people with diabetes have about 2.5 times the level of hospital use compared to people without diabetes (Figure 3.15). As might be expected, older adults had more days in hospital than younger adults, and people with diabetes used more hospital services across all ages (Figure 3.16). Younger adults with diabetes had 3 to 5 times more hospital days in 2005 than their non-diabetic counterparts.

A leading cause of hospitalization for people with diabetes was CVD, accounting for 18% of admissions in Alberta in 2005, compared to 9% of hospitalizations for people without diabetes. In 2005, people with diabetes were 2 to 4 times more likely to be hospitalized for cardiovascular or renal disease, and more than 16 times as likely to have lower limb amputations compared to people without diabetes (Figure 3.17).

As with other health services, there was considerable variation in the number of hospital days for residents of the different health regions across Alberta, but the ratio for people with and without diabetes was similar (Figure 3.18). After adjusting for age and sex differences, people with diabetes living in Calgary and Capital had the fewest days in hospital in 2005, while people with diabetes living in David Thompson, Peace Country and Northern Lights had the most days in hospital.

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

DiabetesNo Diabetes

2.5

2.0

1.5

1.0

0.5

0

3.15

Ave

rage

Num

ber

of D

ays

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

6

5

4

3

2

1

0

9

8

7

6

5

4

3

2

1

0

Age Group (Years)

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Rat

io( D

iabe

tes:

No

Dia

bete

s)

Ave

rage

Num

ber

of D

ays

3.16

Diabetes

No Diabetes

DiabetesNo Diabetes

2.5

2.0

1.5

1.0

0.5

0

3.15

Ave

rage

Num

ber

of D

ays

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

6

5

4

3

2

1

0

9

8

7

6

5

4

3

2

1

0

Age Group (Years)

20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Rat

io( D

iabe

tes:

No

Dia

bete

s)

Ave

rage

Num

ber

of D

ays

3.16

Diabetes

No Diabetes

Figure 3.15 Age and Sex-Adjusted Hosp�tal Days, ����-�00�

Figure 3.16 Age-Spec�fic Hosp�tal Days, �00�

Page 45: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

16.2

4.1

2.42.9

3.9

2.5 2.72.0

Amputations KidneyDisease

CVD Hypertension HeartFailure

Acute MyocardialInfarction

IschemicHeart Disease

Stroke

3.17

18

16

14

12

10

8

6

4

2

0

Rat

e R

atio

(D

iabe

tes:

No

Dia

bete

s)

Diabetes

No Diabetes

Ave

rage

Num

ber

of H

ospi

tal D

ays

3.0

2.5

2.0

1.5

1.0

0.5

0

3.18

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes Provincial Average = 1.8

16.2

4.1

2.42.9

3.9

2.5 2.72.0

Amputations KidneyDisease

CVD Hypertension HeartFailure

Acute MyocardialInfarction

IschemicHeart Disease

Stroke

3.17

18

16

14

12

10

8

6

4

2

0

Rat

e R

atio

(D

iabe

tes:

No

Dia

bete

s)

Diabetes

No Diabetes

Ave

rage

Num

ber

of H

ospi

tal D

ays

3.0

2.5

2.0

1.5

1.0

0.5

0

3.18

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes Provincial Average = 1.8

Figure 3.17 Age-Adjusted Hosp�tal�zat�on Rate Rat�o for Selected Cond�t�ons, �00�

Figure 3.18 Age and Sex-Adjusted Hosp�tal�zat�on Days by Reg�on, �00�

Page 46: ALBERTA DIABETE S ATLA S 2007

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CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

DISCUSSION

The findings of increased utilization of all health care services for people with diabetes in Alberta are similar to patterns reported in most other jurisdictions.(2,4) In general, people with diabetes use 2 to 3 times the amount of health services compared to people without diabetes. Therefore, at any given unit cost for these health care services, people with diabetes cost our health care system 2 to 3 times as much as people without diabetes. This is not to say that these increased costs are not necessary or valuable, but speaks to the growing burden on our health care system as the prevalence continues to increase.

This is highlighted by the difference between average use of health care and the total number of visits or encounters. For example, while the average number of GP visits for people with diabetes has remained fairly stable over the past decade, the actual total number of GP visits has doubled. The same picture was seen for visits to specialist physicians over the same time period. In light of the well-recognized shortage of health care professionals, these patterns continue to raise concerns for the quality of care for people with diabetes. It is also clear from these findings that use of health care services increases with age for people with and without diabetes. With our provincial population growing more every year due to immigration, coupled with a shift to an older age demographic, a need for health care services will continue to be in high demand.

Due to the growing number of complications in people with diabetes, these higher rates of services and care, demonstrated by the findings of this chapter, are likely necessary. In fact, studies in Alberta(5-8) and other provinces in Canada(9-12) suggest that the current levels of care may actually be sub-optimal in managing the risk of developing complications for people with diabetes. It is important to recognize that enhancing the quality of care for people with diabetes to the levels recommended in clinical practice guidelines(3) may actually require an increase in utilization of certain health care services to avoid devastating and costly complications down the road.(13)

On that note, there was one good news story in the findings of this chapter. We observed a decline in the percentage of emergency department visits for cardiovascular disease over the past five years. This pattern is also evident in the data presented in the Diabetes and Cardiovascular Disease chapter. While the total number of emergency department visits has increased, the number of visits for cardiovascular disease has remained fairly stable in the past 5 years. This is in contrast to the overall trends of service utilization, which have increased with the growing population, and therefore may represent some degree of success in reducing cardiovascular complications for people with diabetes.

When variation in health services across health regions was considered, several patterns emerged suggesting access to certain health services impact on use of other services. One important aspect of the overall care for people with diabetes is the combination of GP and specialists services.(14,15) It is generally agreed that the majority of medical care for people with diabetes should be from GPs.(3) Overall, we see that people with diabetes see a GP three times more often than they see a specialist, but in more recent years, the relative use

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ALBERTA DIABETES ATLAS 2007 ��

of specialists has increased. This trend is associated with higher health care costs, again speaking to the need for effective prevention and management strategies for people with diabetes. What is not considered in the data presented in this chapter are the long-term outcomes associated with the different mix of available services (e.g., GP vs. specialist care).

There was also considerable variation in access to physicians across the province. For example, people with diabetes living in Calgary or Capital region were less likely to see a GP, but more likely to see a specialist than people with diabetes living in remote or non-metro regions. Further, people with diabetes living in Aspen and Peace Country regions were far more likely to have emergency department encounters than other regions. Information such as this can be helpful to policy-decision makers and planners with respect to the distribution of health services throughout Alberta.

It is important to note that the findings presented in this chapter of the Alberta Diabetes Atlas provide only a general overview of selected health care services for people with diabetes. It is by no means a complete picture. We do not have information, for example, on access and use of diabetes education centers and the use of many allied health professionals who care for people with diabetes, such as nurses, dieticians, pharmacists, podiatrists, etc. As these services are generally managed privately or regionally within their own global budgets, there are no central databases which capture information on utilization of these health care providers. Nonetheless, given the findings that we see for physician and acute care services, there is every reason to believe that the demand for all health care services for people with diabetes is continuing to increase.(13,16) Centralized and population-based information on use of laboratory services or use of prescription drugs for seniors could be captured and reported on in future versions of the Alberta Diabetes Atlas.

It is possible to evaluate the use of some regional diabetes care services, such as the recently published report from Calgary Health region describing the association between socioeconomic status and use of health care services for people with diabetes.(17) Though not specifically considered in this chapter, it is becoming clear that people with lower incomes are more likely to develop diabetes, and to subsequently use more health services than people without diabetes.(17,18) This report from Calgary suggests there is no income bias in terms of access to diabetes education services, but nonetheless, others have also called for attention to the potential disparities in health for vulnerable populations.(13,18,19)

In presenting information on utilization of health care services, we condensed and summarized a tremendous amount of data into more easily digestible portions. We recognize, however, that this sometimes conceals the detail that may be desirable for making specific decisions. For example, we reported physician visits on a composite indicator of selected specialists, but included only six specialist categories: cardiologists, endocrinologists, internists, nephrologists, ophthalmologists and psychiatrists, as they represented the most relevant specialists for topics covered in this first version of the Alberta Diabetes Atlas.

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CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

References 1. Ettaro L, Songer TJ, Zhang P, Engelgau MM. Cost-of-illness studies in diabetes mellitus. Pharmacoeconomics

2004 ;22(3) :149-64. Review.

2. Johnson JA, Pohar, SL, Majumdar SR. Health care use and costs in the decade after identification of type 1 and type 2 diabetes: a population-based study. Diabetes Care 2006;29:2403-2408.

3. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. 2003 clinical practice guidelines for the prevention and treatment of diabetes. Can J Diabetes 2003;27:Suppl 2.

4. Chan BTB, Harju M. Supply and Utilization of Health Care Services for Diabetes: In Hux J E, Booth G L, Slaughter P M, Laupacis A (eds). Diabetes in Ontario: An ICES Practice Atlas: Institute for Clinical Evaluative Sciences. 2003: 14.249-14.268.

5. Toth EL, Majumdar SR, Guirguis LM, Lewanczuk RZ, Lee TK, Johnson JA. Compliance with clinical practice guidelines for type 2 diabetes in rural patients: treatment gaps and opportunities for improvement. Pharmacotherapy 2003;23(5):659-665.

6. Klinke JA, Johnson JA, Guirguis LM, Toth EL, Lee TK, Lewanczuk RZ, Majumdar SR. Underuse of aspirin in type-2 diabetes mellitus: prevalence and correlates of therapy in rural Canada. Clin Ther. 2004;26:439-446.

7. Rucker D, Johnson JA, Lee TK, Eurich DT, Lewanczuk RZ, Simpson SH, Majumdar SR. The natural history of LDL control in type-2 diabetes: a prospective study of adherence to lipid guidelines. Diabetes Care 2006;29:2506-2509.

8. Supina AL, Guirguis LM, Majumdar SR, Lewanczuk RZ, Lee TK, Toth EL, Johnson JA. Treatment gaps for hypertension management in rural Canadian patients with type 2 diabetes mellitus. Clin Ther 2004;26:598-606.

9. Alter DA, Khaykin Y, Austin PC, Tu JV, Hux JE. Processes and outcomes of care for diabetic acute myocardial infarction patients in Ontario: do physicians undertreat? Diabetes Care 2003;26:1427-34.

10. Brown LC, Johnson JA, Majumdar SR, Tsuyuki RT, McAlister FA. Evidence of sub-optimal cardiovascular risk management in patients with type 2 diabetes mellitus and symptomatic atherosclerosis. CMAJ 2004;171(10):1189-92.

11. Shah BR, Mamdani M, Jaakkimainen L, Hux JE. Risk modification for diabetic patients. Are other risk factors treated as diligently as glycemia? Can J Clin Pharmacol. 2004;11:e239-44

12. Chan BTB, Klomp H, Cascagnette P. Quality of Diabetes Management in Saskatchewan. Saskatoon: Health Quality Council. January 2006.

13. Health Council of Canada. Why Health Care Renewal Matters: Lessons from Diabetes. Toronto, ON. March 2007 ISBN 0-9780488-2-2.

14. Shah BR, Hux JE, Laupacis A, Zinman B, van Walraven C. Clinical inertia in response to inadequate glycemic control: do specialists differ from primary care physicians? Diabetes Care 2005;28(3):600-6.

15. McAlister FA, Majumdar SR, Eurich DT, Johnson JA. The impact of specialist care within the first year on subsequent outcomes in 24,232 adults with new onset diabetes mellitus: population-based cohort study. Qual & Saf Health Care 2007;16:6-11.

16. Shiu J, Simpson SH, Johnson JA, Tsuyuki R. Quantifying opportunities to affect diabetes management in the community. CPJ-RPC 2006;139(3):37-38.

17. Rabi DM, Edwards AL, Southern DA, Svenson LW, Sargious PM, Norton P, Larsen ET, Ghali WA. Association of socio-economic status with diabetes prevalence and utilization of diabetes care services. BMC Health Serv Res. 2006;6:124.

18. Gulliford MC, Mahabir D, Rocke B. Diabetes-related inequalities in health status and financial barriers to health care access in a population-based study. Diabet Med. 2004;21:45-51.

19. Booth GL, Hux JE. Relationship between avoidable hospitalizations for diabetes mellitus and income level. Arch Intern Med. 2003;163:101-6.

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CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ��

APPENDIX

Alberta Physician Claims Data

D�agnos�s Procedure Code Descr�pt�on

Lower.Limb.Amputation 96.11A Amputation.and.disarticulation.of.one.toe

96.12A Amputation.and.disarticulation.of.foot:.Metatarsal-.whole.ray

96.12B Amputation.and.disarticulation.of.foot:.Transmetatarsal

96.13 Amputation.and.disarticulation.of.ankle:.Symes,.Pirogoff

96.14 Amputation.of.lower.leg.below.knee

96.15 Amputation.of.thigh.or.disarticulation.of.knee:.Supracondylar.Thigh.through.femur

Excluded D�agnost�c Codes ICD-�-CM Descr�pt�on

170 Malignant.bone.tumor

171 Malignant.connective.tissue.tumor

213 Benign.neoplasm.of.bone

730 Osteomyelitis

740-759 Congenital.abnormalities

800-900 Trauma

901-904 Arterial.Injury

940-950 Burns

Ambulatory Care Classification System

D�agnos�s ICD-�-CM ICD-�0-CA

Glycemic.Emergencies.

Diabetic.Ketoacidosis 250.1 E10.1-E14.1

Diabetic.Coma 250.2,.250.3,.251.0 E10.0-E14.0

Cardiovascular.Disease 390-448 I00-I78

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CHAPTER �DIABETES AND HEALTH CARE UTILIZATION IN ALBERTA

Discharge Abstracts Database

D�agnos�s ICD-�-CM ICD-�0-CA

Cardiovascular.Disease 390-448 I00-I78

Ischaemic.Heart.Disease 410-414 I20-I25

Hypertensive.Disease 401-405 I10-I13,I15

Acute.Myocardial.Infarction 410 I121-I22

Heart.Failure 428 I50

Stroke 430-438 I60-I69,.G45.X

Chronic.Kidney.Disease 585-586 N18-N19

Page 51: ALBERTA DIABETE S ATLA S 2007

ALBERTA DIABETES ATLAS 2007 ��

Chapter � D�abetes and Card�ovascular D�sease �n Alberta

Acute Coronary Syndrome and D�abetes

Michelle Graham

Colleen Norris

Sumit R. Majumdar

Jeffrey A. Johnson

Heart Fa�lure and D�abetesFinlay A. McAlister

Dean T. Eurich

Stroke and D�abetesScot H. Simpson

Hude Quan

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�� ALBERTA DIABETES ATLAS 2007

Page 53: ALBERTA DIABETE S ATLA S 2007

ALBERTA DIABETES ATLAS 2007 ��

CHAPTER �

DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA

Acute Coronary Syndrome and D�abetes

KEY MESSAGES

• People with diabetes are 2.5 times more likely to suffer heart attacks or episodes of unstable angina than people without diabetes.

• Overall, rates of heart attacks and unstable angina have decreased considerably in the past decade. In those with diabetes, these rates have stabilized and even slightly decreased.

• Rates of coronary revascularization procedures have increased over the past decade, with increased use of PCI compared to CABG; people with diabetes are 2 to 4 times more likely to require these interventions than people without diabetes.

• There were differences in the relative use of PCI and CABG for people with diabetes across health regions.

BACKGROUND

The primary cause of mortality in patients with type 2 diabetes is cardiovascular disease.(1) Most of this excess mortality risk is attributable to damage to the coronary blood vessels due to atherosclerotic disease, which can lead to unstable angina and acute myocardial infarction (i.e., heart attack).(1) The burden of heart disease in the diabetes population has been studied extensively, including numerous reports in Canadian population.(2,3) In addition to the increased morbidity and mortality, cardiovascular disease is also a leading driver of health care costs for people with diabetes.(4)

The population burden of heart disease can be reported in several ways. In this chapter of the Alberta Diabetes Atlas, we report on the clinical outcomes of acute myocardial infarction (AMI) and unstable angina, as well as major procedures used to remove blockages in blood flow in the heart, focusing on percutaneous coronary interventions (PCI) and coronary artery bypass graft (CABG) surgery. PCI is a procedure where a catheter is inserted into a peripheral blood vessel and threaded into the heart and coronary blood vessels, where a tiny balloon is inflated to reduce blockages. Generally, a mesh tube, called a stent, is opened up inside the coronary vessel to keep the blocked area open. CABG involves open heart surgery, and inserting bypass grafts (arteries or veins from other areas of the body) on the heart to detour blood flow around the blockages in the coronary vessels.

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

METHODS

Data from Alberta Health and Wellness administrative databases were utilized for these analyses, which capture Alberta resident demographic information for all physician visits and procedures. People with diabetes were identified within the Alberta Health and Wellness databases by applying the NDSS algorithm (see Methods chapter). All adult patients aged 20 or greater were included in these analyses.

We abstracted diagnostic codes for AMI and unstable angina from the provincial Discharge Abstracts Database (see Appendix). Taken together, these diagnoses were considered to represent acute coronary syndrome (ACS). We also abstracted procedure codes for CABG and PCI from the Physician Claims database (see Appendix). Of note, rates of revascularization procedures were not restricted to acute syndromes, but included elective procedures as well.

From these data, rates of ACS for those with and without diabetes were calculated. For each group, the number of people with ACS diagnostic or procedure codes (numerator) was divided by the total number of people in the province or region (denominator), respectively. As with other rates in the Atlas, we used a direct standardization to age and sex adjust rates of ACS using the Alberta population from the 2001 Canadian Census. We present trends of ACS or coronary procedures over time (1995 to 2005 unless otherwise specified), and across age groups and health regions for the most recent year (2005).

FINDINGS

Acute Coronary SyndromeFrom 1995 to 2005, the prevalence rate of ACS has declined in both the general population and in people with diabetes (Figure 4.1). The actual number of people suffering from ACS, however, has remained fairly stable in people without diabetes over that time, at about 4600-4800 people per year (Figure 4.2). A different picture is seen when observing people with diabetes, where cases of ACS increased dramatically from 1995 to 2002, but have since leveled off, or even begun to decrease (Figure 4.3). In those with diabetes, approximately 60% of the total number of ACS cases were made up of AMI cases from 1995-2005.

In 2005, people with diabetes were more than 2.5 times more likely to have ACS than people without diabetes. While older individuals were more likely to have ACS overall, the excess risk associated with diabetes was much higher in younger adults, compared to their non-diabetic counterparts (Figure 4.4).

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

6000

5000

4000

3000

2000

1000

0

Female

Male

Total

4622 47204540 4545 4532 4579 4644 4754 4835

4689 4557

Year

Num

ber

of C

ases

4.2

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

10

9

8

7

6

5

4

3

2

1

0

Year

Rat

e pe

r 10

004.1

Diabetes

No Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

6000

5000

4000

3000

2000

1000

0

Female

Male

Total

4622 47204540 4545 4532 4579 4644 4754 4835

4689 4557

Year

Num

ber

of C

ases

4.2

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

10

9

8

7

6

5

4

3

2

1

0

Year

Rat

e pe

r 10

004.1

Diabetes

No Diabetes

Figure 4.1 Age and Sex-Adjusted Rates of Acute Coronary Syndrome, ����-�00�

Figure 4.2 Acute Coronary Syndrome Cases for those w�thout D�abetes, ����-�00�

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�0 ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

Female

Male

Total

10191085

1130 1126 11571216

1260

1413 14261380 1375

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

1600

1400

1200

1000

800

600

400

200

0

Year

Num

ber

of C

ases4.3

Rat

e pe

r 10

00

25

20

15

10

5

0

4-4

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Diabetes

No Diabetes

Female

Male

Total

10191085

1130 1126 11571216

1260

1413 14261380 1375

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

1600

1400

1200

1000

800

600

400

200

0

Year

Num

ber

of C

ases4.3

Rat

e pe

r 10

00

25

20

15

10

5

0

4-4

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Diabetes

No Diabetes

Figure 4.3 Acute Coronary Syndrome Cases for those w�th D�abetes, ����-�00�

Figure 4.4 Age-Spec�fic Rates of Acute Coronary Syndrome, �00�

Page 57: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

Rat

e pe

r 10

00

12

10

8

6

4

2

0

4.5

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Rat

e pe

r 10

00

10

9

8

7

6

5

4

3

2

1

0

4-6

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes

No Diabetes

Diabetes

No Diabetes

Rat

e pe

r 10

00

12

10

8

6

4

2

0

4.5

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Rat

e pe

r 10

00

10

9

8

7

6

5

4

3

2

1

0

4-6

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes

No Diabetes

Diabetes

No Diabetes

There was variation in frequency of ACS across health regions in 2005, although the 2.5 ratio between those with and without diabetes was generally similar (Figure 4.5). After adjusting for age, the highest rates of ACS were seen in Palliser, David Thompson, Aspen and Peace Country, while Capital and Calgary had similarly lower rates of ACS. A similar picture is evident for AMI alone, although for this outcome, East Central had the lowest rate in the province in 2005 (Figure 4.6).

Figure 4.5 Age-Adjusted Rates of Acute Coronary Syndrome by Reg�on, �00�

Figure 4.6 Age-Adjusted Rates of Acute MI by Reg�on, �00�

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

Year

Rat

e pe

r 10

004-8

Diabetes

No Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

5

4

3

2

1

0

Year

Rat

e pe

r 10

00

4.7

Diabetes

No Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

Year

Rat

e pe

r 10

004-8

Diabetes

No Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

5

4

3

2

1

0

Year

Rat

e pe

r 10

00

4.7

Diabetes

No Diabetes

Revascularization ProceduresThere has been some variation in the rate of PCI and CABG for people with diabetes over the past decade. PCI rates have gradually increased from 1995-2005 (Figure 4.7). CABG rates increased initially, but then decreased in the last 4 years (Figure 4.8). The total number of revascularization procedures for those with and without diabetes has grown over the past decade, particularly due to increased use of PCI (Figure 4.9).

Figure 4.7 Age and Sex-Adjusted Rates of PCI, ����-�00�

Figure 4.8 Age and Sex-Adjusted Rates of CABG, ����-�00�

Page 59: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

Rat

e pe

r 10

00

10

8

6

4

2

0

4.10

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes

No Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

7000

6000

5000

4000

3000

2000

1000

0

Year

Num

ber

of P

roce

dure

s

4-9

CABG - Diabetes

CABG - No Diabetes

PCI - Diabetes

PCI - No Diabetes

CABG

PCI

Rat

e pe

r 10

00

10

8

6

4

2

0

4.10

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes

No Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

7000

6000

5000

4000

3000

2000

1000

0

Year

Num

ber

of P

roce

dure

s

4-9

CABG - Diabetes

CABG - No Diabetes

PCI - Diabetes

PCI - No Diabetes

CABG

PCI

Figure 4.9 Total Number of PCI and CABG Procedures, ����-�00�

There was variation in rates of CABG and PCI for people living in different health regions. For people with diabetes, the highest rates of PCI were seen for those living the northern regions of the province; and the lowest rates were found in Chinook and East Central (Figure 4.10). There was less variation in CABG rates across the province. While Calgary and Capital had high rates (Figure 4.11), the wide confidence intervals for CABG surgery rates in the other regions make it difficult to draw conclusions about these apparent differences.

Figure 4.10 Age-Adjusted Rates of PCI by Reg�on, �00�

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Year

PCI t

o C

ABG

Rat

io

4.12

Diabetes

No Diabetes

Rat

e pe

r 10

00

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

4-11

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes

No Diabetes

Figure 4.11 Age-Adjusted Rates of CABG by Reg�on, �00�

The ratio of PCI to CABG provides an interesting perspective on the preference for the two revascularization procedures, and also demonstrates differences in the management of CVD in people with diabetes. In the non-diabetes population this ratio has increased from 1.6 in 1995 to over 2.5 in 2005 (Figure 4.12). This means that PCI was becoming much more popular in the non-diabetes population over this time period. Interestingly, the ratio of PCI to CABG has generally been lower for people with diabetes most years. The PCI to CABG ratio differed considerably for residents of different regions (Figure 4.13). PCI was approximately twice as likely as CABG for most of the regions, with the exceptions of Calgary, Peace Country and Northern Lights, where the ratios were even greater. Compared to people without diabetes, people with diabetes had a lower ratio of PCI to CABG in southern Alberta. Similar ratios of PCI to CABG were found in central Alberta, and a higher ratio, approximately 5 times more likely, in Peace Country and Northern Lights.

Page 61: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

ALBERTA DIABETES ATLAS 2007 ��3416 3549 3821 4031

4424 4698 4965 5114 53165709

6139

1400314452

1508515444

16610 16926 1695016335 16398

16807 16934

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Year

Num

ber

of C

ases4-14

Diabetes

No Diabetes

Diabetes

No Diabetes

PCI t

o C

ABG

Rat

io

6

5

4

3

2

1

0

4.13

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Year

PCI t

o C

ABG

Rat

io

4.12

Diabetes

No Diabetes

Rat

e pe

r 10

00

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

4-11

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes

No Diabetes

Figure 4.12 Age and Sex-Adjusted Rat�os of PCI to CABG, ����-�00�

Figure 4.13 Age-Adjusted Rat�os of PCI to CABG by Reg�on, �00�

Page 62: ALBERTA DIABETE S ATLA S 2007

�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Acute Coronary Syndrome and Diabetes

DISCUSSION

Cardiovascular disease is clearly one of the most important comorbidities in people with diabetes. It is the leading cause of death(3,5,6) and one of the largest drivers of health care costs in people with diabetes.(4) In this section of the Alberta Diabetes Atlas, we reported on both clinical outcomes of ACS (heart attacks and angina) as well as the major revascularization procedures used to manage this condition (PCI and CABG). Both indicators tell a similar bad-news, good-news story. The bad news is that the burden of heart disease continues to grow in the diabetes population, but the good news is that some success has been achieved in reducing the risk of these severe outcomes.

There is an abundance of evidence for numerous strategies of reducing cardiovascular risk, including drug therapy for blood pressure reduction, cholesterol reduction and anti-platelet therapy (e.g., ASA). More widespread use of evidence-based drug treatments have surely decreased patients’ risk of cardiovascular death.(3,6,7) Similar evidence of substantially reduced cardiovascular mortality and morbidity in Ontario between 1992 and 2000 has also been reported.(3) In addition to drug therapies, behavioral changes including weight loss and smoking cessation are also important to consider. All of these risk reduction strategies are supported by the highest level of evidence.(5)

Unfortunately, by all estimates, the attention to reducing cardiovascular risk in patients with diabetes remains dismally poor,(8-11) including evidence from Alberta.(12-14) The under-treatment of cardiovascular risk remains a problem, even after a major event such as a heart attack.(15) There is likely room for a lot of improvement by using aggressive risk reduction in this population.

The trends in PCI and CABG over time and variation across regions reported in this Alberta Diabetes Atlas are very similar to the rates reported recently by the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH)(16) and the Canadian Cardiovascular Outcomes Research Team (CCORT).(17,18) Using data collected directly from cardiac catheterization laboratories in Calgary and Capital, APPROACH has also demonstrated increased use of PCI relative to CABG over the past decade. Similar regional variation was also reported by APPROACH, with lower rates of both PCI in regions serviced by Calgary compared to Capital and the more northern regions.(16)

Diabetes clearly places an increased burden on the Alberta health care system, with rates of PCI and CABG at 2 to 4 times higher for people with diabetes than without. Interestingly, the north to south gradient for CABG rates seen in the general population is not apparent for people with diabetes. In the Calgary region for example, people with diabetes are much more likely to have CABG relative to their non-diabetic counterparts than individuals living in northern regions. The ratio of PCI to CABG suggests that people with diabetes and heart disease living in northern Alberta are managed quite differently than people with or without diabetes living in the rest of the province. Previous reports from the APPROACH data have suggested similar patterns, with only the population in the far north of the province being more likely to have undergone revascularization.(19) Reasons for these different patterns of care and whether these differences in management actually lead to different outcomes(20) should be explored.

Page 63: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Hear t Fa i lure and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA

Heart Fa�lure and D�abetes

KEY MESSAGES

• Heart failure is 2.5 times more common in people with diabetes than in people without diabetes.

• Rates of heart failure are generally similar in people with diabetes living in all regions of the province.

• People with diabetes are 10 times more likely to have an emergency department visit or be hospitalized due to heart failure compared to those without diabetes.

• Of those admitted to hospital for heart failure, people with diabetes stay in hospital 1 day longer than people without diabetes.

BACKGROUND

Heart failure (HF) causes significant morbidity and mortality. One year mortality rates remain as high as 20-30%, even with optimal drug therapy.(21,22) In addition, HF exerts a substantial burden on the health care system. It is the most common primary diagnosis in North America for people over age 65 years as well as the fastest growing cardiovascular diagnosis in North America.(23,24) In 2007, over $35 billion in health care costs and lost productivity will be attributable to HF.(22) Indeed, the lifetime risk of developing HF is estimated at one in five in North America.(25)

Diabetes is a strong risk factor for the development of HF, particularly in women.(26,27) In patients with diabetes, poor glucose control is associated with a higher risk of developing HF.(28-30) HF is a common complication in the diabetes population.(30-32) The combination of diabetes and heart failure is known to result in worse outcomes compared to having either condition alone. For example, exacerbation of HF, increased hospitalization and health care costs, and increased mortality occur more often in those with HF and diabetes.(32-36) A recent community-based study from the United States reported that the prevalence of diabetes is increasing in patients with HF such that elderly patients with newly diagnosed HF in 1999 were four times more likely to have concomitant diabetes as patients newly diagnosed with HF in 1979.(35)

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�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Hear t Fa i lure and Diabetes

HF is often a forgotten comorbidity for people with diabetes, despite the shared risk factors and the tremendous impact it has on people with diabetes and our health care system.(31) We have therefore highlighted this important condition in this chapter of the Alberta Diabetes Atlas. Different perspectives on the burden of HF in Alberta are provided by comparing the prevalence of HF in those with and without diabetes over the past decade, and across the health regions in Alberta. Emergency department usage and hospitalization for HF in people with and without diabetes will also be compared.

METHODS

Data from Alberta Health and Wellness (AHW) administrative databases were utilized for these analyses. This dataset captures Alberta resident demographic information, and heart failure diagnoses (see Appendix) in the physician claims data, hospital data, and/or emergency department data. All adult residents of Alberta aged 20 years or greater were included in these analyses.

From these data, rates of heart failure for those with and without diabetes were calculated. For each group, the number of people with heart failure (numerator) was divided by the number of people in the province or region (denominator), respectively.

Persons with diabetes were identified as described in the Methods chapter. Trends over time (1995-2005), as well as regional and age-specific rates for heart failure were calculated. Heart failure-related hospitalizations and emergency department encounters were also ascertained and rates for people with and without diabetes were compared. As many hospital admissions represent transfers from one site to another, we are reporting emergency department visits and hospitalizations as the rate of individuals with one or more visit per year.

As with other rates in the Atlas, direct standardization was used to adjust rates by age and sex for comparisons across time and regions, using the Alberta population according to the 2001 Canadian Census.

FINDINGS

The number of people in Alberta with a physician claim for a diagnosis of HF has steadily increased over the past decade (Figure 4.14). Increases in HF over the last 5 years are due mainly to an increase in HF in people with diabetes. Overall, about 27% of adults with HF have diabetes. Among all adults with diabetes, approximately 5% have HF, which increases to over 9% in those over the age of 65 years. However, as the total number of people with diabetes has also increased over this time period, the prevalence rate of HF in people with diabetes has actually decreased (Figure 4.15). A decrease in the number of cases with HF was also seen in people without diabetes. Each year over the past decade, HF diagnoses are about 2.5 times more common in people with diabetes compared to people without diabetes.

Page 65: ALBERTA DIABETE S ATLA S 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Hear t Fa i lure and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

25

20

15

10

5

0

Year

Rat

e pe

r 10

00

4.15

Diabetes

No Diabetes

Rat

e pe

r 10

00

140

120

100

80

60

40

20

0

4-16

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Diabetes

No Diabetes

3416 3549 3821 40314424 4698 4965 5114 5316

57096139

1400314452

1508515444

16610 16926 1695016335 16398

16807 16934

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Year

Num

ber

of C

ases4-14

Diabetes

No Diabetes

Diabetes

No Diabetes

PCI t

o C

ABG

Rat

io

6

5

4

3

2

1

0

4.13

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Figure 4.14 Number of Heart Fa�lure Cases, ����-�00�

Figure 4.15 Age and Sex-Adjusted Rates of Heart Fa�lure, ����-�00�

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�0 ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Hear t Fa i lure and Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

25

20

15

10

5

0

Year

Rat

e pe

r 10

00

4.15

Diabetes

No Diabetes

Rat

e pe

r 10

00

140

120

100

80

60

40

20

0

4-16

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Diabetes

No Diabetes

Diabetes

No Diabetes

Rat

e pe

r 10

00

35

30

25

20

15

10

5

0

4.17

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

0.12 0.13 0.12

1.08

1.30

1.19

No Diabetes Diabetes

1.4%

1.2%

1.0%

0.8%

0.6%

0.4%

0.2%

0%

Perc

ent

with

One

or

Mor

e V

isit

4.18

Female

Male

Total

As with other cardiovascular diseases, HF is more common in older adults. People with diabetes in the younger age groups, however, are also more likely to have HF compared to their non-diabetic counterparts (Figure 4.16). The rate of HF in people with and without diabetes appears to be similar across all of the health regions in Alberta in 2005 (Figure 4.17).

Figure 4.16 Age-Spec�fic Rates of Heart Fa�lure, �00�

Figure 4.17 Age-Adjusted Rates of Heart Fa�lure by Reg�on, �00�

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Hear t Fa i lure and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

Diabetes

No Diabetes

Rat

e pe

r 10

00

35

30

25

20

15

10

5

0

4.17

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

0.12 0.13 0.12

1.08

1.30

1.19

No Diabetes Diabetes

1.4%

1.2%

1.0%

0.8%

0.6%

0.4%

0.2%

0%

Perc

ent

with

One

or

Mor

e V

isit

4.18

Female

Male

Total

1152212255

12669 1289013333

1377014152 14347 14241

15271 15270

2183 2330 2358 2417 2508 2768 2915 2926 3016 3260 3566

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Year

Num

ber

of C

ases4-20

Diabetes

No Diabetes

0.93 0.97 0.95

9.00

10.30

9.64

No Diabetes Diabetes

12

10

8

6

4

2

0

Rat

e pe

r 10

00 o

f One

or

Mor

e H

ospi

taliz

atio

n

4.19

Female

Male

Total

People with diabetes are approximately 10 times more likely to have at least one visit to the emergency department (Figure 4.18) or be hospitalized for HF (Figure 4.19) than people without diabetes. For those admitted to hospital for HF, people with diabetes stay in-hospital 1 day longer than people without diabetes (median stay 9 days versus 8 days), although after adjusting for the older age of people with diabetes, the lengths of stay are quite similar.

Figure 4.18 Rates of Emergency Department V�s�ts for Heart Fa�lure, �00�

Figure 4.19 Hosp�tal�zat�on Rate for Heart Fa�lure, �00�

Page 68: ALBERTA DIABETE S ATLA S 2007

�� ALBERTA DIABETES ATLAS 2007

CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Hear t Fa i lure and Diabetes

DISCUSSION

The data presented in this section confirms the well-known relationship that heart failure is a common comorbidity in patients with diabetes. It also confirms that patients with diabetes have a higher risk of heart failure than their age and sex matched controls. Like other cardiovascular conditions presented in the Alberta Diabetes Atlas, we have seen a decline in the prevalence rate of HF in the diabetes population in recent years. However, as the total number of people with diabetes continues to increase, so are the numbers of HF cases.

This trend will continue to result in substantial morbidity and mortality among the diabetes population in coming years.(33) The increasing number of people with HF in the diabetes population is likely to place a greater burden on our health care system as well. This is evidenced by the rates of visits to the emergency department and admissions to hospital for HF being 10 times higher in people with diabetes than in people without diabetes. A decline in the rates of hospitalization and average length of stay for HF was observed nationally in Canadian data from 1994 to 1999.(17) In 2005, in Alberta, we observed that the length of stay for HF admissions is 1 day longer for people with diabetes, which translates into substantially higher health care costs.

Since diabetes is associated with worse outcomes in patients with HF, use of evidence-based therapies to improve outcomes is imperative.(7,32,37) Unfortunately, therapies which are proven to improve HF outcomes are underused in the diabetes population.(7,9,12) Randomized trial evidence suggests that people with HF achieve better outcomes when they receive specialist care and/or are actively followed by multidisciplinary teams.(38) Equally important is the active role of the patient with HF in self-management strategies, such as making dietary changes, daily recording of body weight and use of a patient diary, all of which are associated with more desirable health outcomes.(39) Increased access to these services and coordination of care for people with HF is necessary in order to have a positive impact on health outcomes for people with diabetes in Alberta.

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Stroke and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA

Stroke and D�abetes

KEY MESSAGES

• Stroke occurs twice as often in people with diabetes compared to people without diabetes.

• People with diabetes have a risk of stroke similar to people without diabetes who are 15 years older.

• Those with diabetes who live in northern or southern Alberta are more likely to suffer a stroke than those who live in central Alberta.

• People with diabetes are over 4.5 times more likely to have an emergency department visit and/or hospital admission for stroke than people without diabetes.

BACKGROUND

Diabetes is a strong and independent risk factor for stroke,(40) which is a major source of morbidity and mortality in Canada.(41) Previous reports suggest that people with diabetes have a two-fold higher risk of stroke compared to the general population.(42,43) This increased stroke risk in people with diabetes is likely due to a higher prevalence of other risk factors, including high blood pressure, high cholesterol, and smoking.(44-46) The growing prevalence of diabetes,(47) coupled with the well-documented treatment gap for cardiovascular risk factors in diabetes,(9,12,48) establishes a strong foundation for early and aggressive stroke prevention strategies.

METHODS

Data from Alberta Health and Wellness (AHW) administrative databases were used in this analysis. The dataset captured Alberta resident demographic information, and stroke diagnoses (see Appendix for the ICD-9 and ICD-10 codes) in the physician claims data, hospital data, and emergency department data. All adult residents of Alberta aged 20 years or greater were included.

From these data, rates of stroke for those with and without diabetes were calculated. For each group, the number of people with stroke (numerator) was divided by the number of people in the province or region (denominator), respectively. Trends over time (1995-2005), as well as regional and age-specific rates for stroke were calculated. Stroke-related hospitalizations and emergency department encounters were also ascertained and rates for people with and without diabetes were compared. Persons with diabetes were identified as described in the

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Stroke and Diabetes

1152212255

12669 1289013333

1377014152 14347 14241

15271 15270

2183 2330 2358 2417 2508 2768 2915 2926 3016 3260 3566

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Year

Num

ber

of C

ases4-20

Diabetes

No Diabetes

0.93 0.97 0.95

9.00

10.30

9.64

No Diabetes Diabetes

12

10

8

6

4

2

0

Rat

e pe

r 10

00 o

f One

or

Mor

e H

ospi

taliz

atio

n

4.19

Female

Male

Total

Methods chapter of this Atlas. As with other rates in the Atlas, direct standardization was used to adjust rates for stroke by age and sex for comparisons across time and regions, using the Alberta population according to the 2001 Canadian Census.

FINDINGS

The number of people suffering a stroke has increased steadily both for those with and without diabetes during the past decade. In 2005, there were almost 19,000 Albertans who had a stroke compared to 13,700 in 1995 (Figure 4.20). After adjusting for differences in age and sex, the annual rate of stroke was significantly higher in people with diabetes compared to people without diabetes (Figure 4.21). From 1995-2005, the rates of stroke for those without diabetes have remained stable at just over 7 per 1000, while rates of stroke for those with diabetes declined from 15 per 1000 in 1995 to 13.6 per 1000 in 2005.

Figure 4.20 Number of Stroke Cases, ����-�00�

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Stroke and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

18

16

14

12

10

8

6

4

2

0

Year

Rat

e pe

r 10

00

4-21

Diabetes

No Diabetes

Rat

e pe

r 10

00

70

60

50

40

30

20

10

0

4-22

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Diabetes

No Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

18

16

14

12

10

8

6

4

2

0

Year

Rat

e pe

r 10

00

4-21

Diabetes

No Diabetes

Rat

e pe

r 10

00

70

60

50

40

30

20

10

0

4-22

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Diabetes

No Diabetes

Figure 4.21 Age and Sex-Adjusted Rates of Stroke, ����-�00�

Although stroke rates are higher in the older age groups in people with and without diabetes, stroke rates were significantly higher in the younger age groups with diabetes compared to their non-diabetic counterparts (Figure 4.22). For example, the rate of stroke in people aged 35-49 with diabetes was similar to those 15 years older without diabetes.

Figure 4.22 Age-Spec�fic Rates of Stroke, �00�

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Stroke and Diabetes

Rat

e pe

r 10

00

25

20

15

10

5

0

4.23

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes

No Diabetes

No Diabetes Diabetes

1.0%

0.9%

0.8%

0.7%

0.6%

0.5%

0.4%

0.3%

0.2%

0.1%

0%

Perc

ent

with

One

or

Mor

e V

isit

4.24

0.22 0.21 0.22

0.80

0.94

0.87Female

Male

Total

In 2005, the overall provincial age-adjusted average for stroke was 7.7 per 1000 Albertans. There was, however, considerable regional variation of stroke rates in the diabetes population, while the rates appear fairly constant among the non-diabetic population (Figure 4.23). People with diabetes living in southern and northern Alberta are more likely to experience stroke than people living closer to central Alberta, with the highest stroke rate being 16 per 1000 people living in the Northern Lights region.

Figure 4.23 Age-Adjusted Rates of Stroke by Reg�on, �00�

In 2005, the rates of emergency department visits for stroke were approximately fourfold higher in people with diabetes compared to those without diabetes (Figures 4.24). Of those who had diabetes, males had higher rates of emergency department visits compared to females. Rates were about the same for males and females in the non-diabetic population.

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Stroke and Diabetes

ALBERTA DIABETES ATLAS 2007 ��

Rat

e pe

r 10

00

25

20

15

10

5

0

4.23

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Diabetes

No Diabetes

No Diabetes Diabetes

1.0%

0.9%

0.8%

0.7%

0.6%

0.5%

0.4%

0.3%

0.2%

0.1%

0%

Perc

ent

with

One

or

Mor

e V

isit

4.24

0.22 0.21 0.22

0.80

0.94

0.87Female

Male

Total

No Diabetes

0.13 0.14 0.13

0.50

0.69

0.60

Diabetes

0.8%

0.7%

0.6%

0.5%

0.4%

0.3%

0.2%

0.1%

0%

Perc

ent

with

One

or

Mor

e H

ospi

taliz

atio

n

4.25

Female

Male

Total

Figure 4.24 Rate of Emergency Department V�s�ts for Stroke, �00�

This difference between males and females with diabetes is even more pronounced in rates of hospitalization for stroke, where males were almost 1.5 times more likely to be hospitalized for stroke than females (Figure 4.25). Males and females without diabetes had about the same rates of hospitalization for stroke. Overall, rates of hospitalization for stroke are about 4.5 times higher among people with diabetes compared to people without diabetes.

Figure 4.25 Hosp�tal�zat�on Rate for Stroke, �00�

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA – Stroke and Diabetes

DISCUSSION

These observations for Alberta confirm previous studies that stroke is more common in people with diabetes compared to those without diabetes.(42-44) As with trends for other cardiovascular diseases, there is a good-news, bad-news story for stroke in the diabetes population in Alberta. While the rates of stroke have decreased over the past decade, the actual number of people suffering from stroke has increased. This is driven by the growing number of people with diabetes in the province.

The increasing number of people with stroke represents the real burden to Albertans and to our health care system. People with diabetes visit the emergency department four to five times more often for stroke than people without diabetes. It is especially important to note that for all ages, people with diabetes have a risk of stroke similar to people 15 years older than them. These numbers highlight the need for strong prevention strategies, to reduce the number of people with diabetes in the first place, but to also reduce the risk of stroke in those who already have the disease.

The differences in stroke rates across the province are an interesting picture to consider. After adjusting for differences in age and sex, we see that people with diabetes living in East Central and David Thompson regions have much lower stroke rates than people with diabetes living in other regions, and particularly for the most southern and northern regions. Somewhat surprisingly, people with diabetes from the Calgary region had higher stroke rates than people with diabetes in Capital region. The reasons for these patterns are not clear, and further investigation into risk factors and prevention strategies should be undertaken.

When interpreting the stroke figures, it is important to note two factors influencing the observed rates. First, a broad definition for stroke was used for the first version of the Alberta Diabetes Atlas to maximize sensitivity, that is, a broader capture of people suffering stroke. We recognize that there may be some difficulty in accurately defining strokes from administrative data.(49-52) In later iterations of the Alberta Diabetes Atlas, this definition will be refined using available, evolving information. Second, we did not differentiate between the type of stroke, which may be ischemic (due to blockages in blood flow) or hemorrhagic (due to bleeding). Further study to examine the different stroke rates according to these causes would therefore be helpful. This information is important for the on-going surveillance of diabetes as a risk factor for stroke and will help to improve stroke prevention strategies in Alberta.

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ALBERTA DIABETES ATLAS 2007 ��

References

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2. Tanuseputro P, Manuel DG, Leung M, Nguyen M, Johansen H. Risk factors for cardiovascular disease in Canada. Can J Cardiol 2003;19(11):1249-1259.

3. Booth GL, Kapral MK, Fung K, Tu JV. Recent trends in cardiovascular complications among men and women with and without diabetes. Diabetes Care 2006;29(1):32-7.

4. Simpson SH, Jacobs P, Corabian P, Johnson JA. The cost of major comorbidity in people with diabetes mellitus. CMAJ 2003;168(13):1661-1667.

5. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. 2003 clinical practice guidelines for the prevention and treatment of diabetes. Can J Diabetes 2003;27:Suppl 2.

6. Gaede P, Vedel P, Larsen N, et al. Multifactorial intervention and cardiovascular disease in patients with type 2 diabetes. N Engl J Med 2003;348:383-93.

7. Eurich DT, Majumdar SR, Tsuyuki RT, Johnson JA. Reduced mortality associated with the use of ACE inhibitors in patients with type 2 diabetes. Diabetes Care 2004;27:1330–1334.

8. Alter DA, Khaykin Y, Austin PC, Tu JV, Hux JE. Processes and outcomes of care for diabetic acute myocardial infarction patients in Ontario: do physicians undertreat? Diabetes Care 2003;26:1427-34.

9. Brown LC, Johnson JA, Majumdar SR, Tsuyuki RT, McAlister FA. Evidence of sub-optimal cardiovascular risk management in patients with type 2 diabetes mellitus and symptomatic atherosclerosis. CMAJ 2004;171(10):1189-92.

10. Chan BTB, Klomp H, Cascagnette P. Quality of Diabetes Management in Saskatchewan. Saskatoon: Health Quality Council. January 2006.

11. Shah BR, Mamdani M, Jaakkimainen L, Hux JE. Risk modification for diabetic patients. Are other risk factors treated as diligently as glycemia? Can J Clin Pharmacol. 2004;11:e239-44.

12. Toth EL, Majumdar SR, Guirguis LM, Lewanczuk RZ, Lee TK, Johnson JA. Compliance with clinical practice guidelines for type 2 diabetes in rural patients: treatment gaps and opportunities for improvement. Pharmacotherapy 2003;23(5):659-665.

13. Supina AL, Guirguis LM, Majumdar SR, Lewanczuk RZ, Lee TK, Toth EL, Johnson JA. Treatment gaps for hypertension management in rural Canadian patients with type 2 diabetes mellitus. Clin Ther 2004;26:598-606.

14. Klinke JA, Johnson JA, Guirguis LM, Toth EL, Lee TK, Lewanczuk RZ, Majumdar SR. Underuse of aspirin in type-2 diabetes mellitus: prevalence and correlates of therapy in rural Canada. Clin Ther 2004;26:439-446.

15. Alter DA, Iron K, Austin PC, Naylor CD; SESAMI Study Group. Socioeconomic status, service patterns, and perceptions of care among survivors of acute myocardial infarction in Canada. JAMA 2004;291(9):1100-7.

16. APPROACH Report: Changes in Diagnostic Cardiac Catheterization and Revascularization Rates for Coronary Heart Disease in Alberta Regional Health Authorities 2003-2005 and Province-Wide Trends 1995-2005. October 2006. www.approach.org

17. Hall RE, Tu JV. Hospitalization rates and length of stay for cardiovascular conditions in Canada, 1994 to 1999. Can J Cardiol 2003;19:1123-1131.

18. Faris PD, Grant FC, Galbraith D, Gong Y, Ghali WA. Diagnostic cardiac catheterization and revascularization rats for coronary heart disease. Can J Cardiol 2004;20:391-397.

19. Seidel JE, Ghali WA, Faris PD, Bow JD, Waters NM Graham MM, Gailbrath PD, Mitchell LB, Knudtson ML. Geographical local of residence and uniformity of access to cardiac revascularization services after catheterization Can J Cardiol 2004;20:5170523.

20. Ghali WA, Quan H, Norris CM, Dzavik V, Naylor CD, Mitchel LB, Brant R, Knudtson ML. Prognostic significance of diabetes as a predictor of survival after cardiac catheterization. Am J Med 2000;109(7):543-8.

21. MacIntyre K, Capewell S, Stewart S, et al. Evidence of improving prognosis in heart failure: trends in case fatality in 66,547 patients hospitalized between 1986 and 1995. Circulation 2000;102:1126-31.

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22. Rosamond W, Flegal K, Friday G, et al. Heart Disease and Stroke Statistics—2007 Update. A Report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation 2007;115:e69-171.

23. Cowie MR, Mosterd A, Wood DA. The epidemiology of heart failure. Eur Heart J 1997;18:208-825.

24. Redfield MM, Jacobsen SJ, Burnett JC Jr, et al. Burden of systolic and diastolic ventricular dysfunction in the community: appreciating the scope of the heart failure epidemic. JAMA 2003;289:194-202.

25. Lloyd-Jones DM, Larson MG, Leip EP, et al. Lifetime risk for developing congestive heart failure: the Framingham Heart Study. Circulation 2002;106:3068-72.

26. Bibbins-Domingo K, Lin F, Vittinghoff E, Barrett-Connor E, Hulley SB, Grady D, Shlipak MG. Predictors of heart failure among women with coronary disease. Circulation 2004;110(11):1424-30.

27. Kannel WB, Hjortland M, Castelli WP. Role of diabetes in congestive heart failure: the Framingham Study. Am J Cardiol 1974;34:29-34

28. Stratton IM, Adler AI, Neil HAW, et al. Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study. BMJ 2000;321:405-412.

29. Iribrarren C, Karter AJ, Go AS, et al. Glycemic control and heart failure among adult patients with diabetes. Circulation 2001;103:2668-2673.

30. Nichols GA, Gullion CM, Koro CE et al. The incidence of congestive heart failure in type 2 diabetes: an update. Diabetes Care 2004;27:1879-1884.

31. Bell DS. Heart failure: the frequent, forgotten, and often fatal complication of diabetes. Diabetes Care 2003;26:2433-2441.

32. Masoudi FA, Inzucchi SE. Diabetes mellitus and heart failure: epidemiology, mechanisms, and pharmacotherapy. Am J Cardiol. 2007;99:113B-132B.

33. De Groote P, Lamblin N, Mouquet F et al. Impact of diabetes mellitus on long-term survival in patients with congestive heart failure. Eur Heart J 2004;25:656-662.

34. Ezekowitz JA, van Walraven C, McAlister FA, Armstrong PW, Kaul P. Impact of specialist follow-up in outpatients with congestive heart failure. CMAJ 2005;172(2):189-94.

35. From AM, Leibson CL, Bursi F, Redfield MM, Weston SA, Jacobsen SJ, Rodeheffer RJ, Roger VL. Diabetes in heart failure: prevalence and impact on outcome in the population. Am J Med 2006;119:591–599.

36. Majumdar SR, McAlister FA, Cree M et al. Do evidence-based treatments provide incremental benefits to patients with congestive heart failure already receiving angiotensin-converting enzyme inhibitors? A secondary analysis of one-year outcomes from the Assessment of Treatment with Lisinopril and Survival (ATLAS) study. Clin Ther. 2004;26:694-703.

37. Eurich DT, Majumdar SR, McAlister FA, Tsuyuki RT, Johnson JA. Improved clinical outcomes associated with metformin in patients with diabetes and heart failure. Diabetes Care 2005;28:2345-2351.

38. McAlister FA, Stewart S, Ferrua S, McMurray JJV. Multidisciplinary strategies for the management of heart failure patients at high risk for admission: A systematic review of randomized trials. J Am Coll Cardiol 2004;44:810-9.

39. Wright SP, Walsh H, Ingley KM, Muncaster SA, Gamble GD, Pearl A, Whalley GA, Sharpe N, Doughty RN. Uptake of self-management strategies in a heart failure management programme. Eur J Heart Fail. 2003;5(3):371-80.

40. D’Agostino RB, Wolf PA, Belanger AJ, Kannel WB. Stroke risk profile: adjustment for antihypertensive medication. The Framingham Study. Stroke 1994;25(1):40-44.

41. Heart and Stroke Foundation of Canada, Canada, Health C, Statistics C, University of Saskatchewan. Heart disease and stroke in Canada. 1995.

42. Kuusisto J, Mykkanen L, Pyorala K, Laakso M. Non-insulin-dependent diabetes and its metabolic control are important predictors of stroke in elderly subjects. Stroke 1994; 25(6):1157-1164.

43. Jeerakathil T, Johnson JA, Simpson SH, Majumdar SR. Short-term risk for stroke is doubled in persons with new type-2 diabetes compared to persons without diabetes: a population-based cohort study. Stroke 2007; in press.

44. Stamler J, Vaccaro O, Neaton JD, Wentworth D. Diabetes, other risk factors, and 12-yr cardiovascular mortality for men screened in the Multiple Risk Factor Intervention Trial. Diabetes Care 1993; 16(2):434-444.

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45. Nathan DM, Meigs J, Singer DE. The epidemiology of cardiovascular disease in type 2 diabetes mellitus: how sweet it is ... or is it? Lancet 1997; 350 Suppl 1:SI4-SI9.

46. Kissela B, Air E. Diabetes: impact on stroke risk and poststroke recovery. Semin Neurol 2006;26(1):100-107.

47. Ohinmaa A, Jacobs P, Simpson SH, Johnson JA. Projections of prevalence and direct cost of diabetes in Canada from 2000 to 2016. Can J Diabetes 2004;28(1):116-123.

48. Grant RW, Cagliero E, Murphy-Sheehy P, Singer DE, Nathan DM, Meigs JB. Comparison of hyperglycemia, hypertension, and hypercholesterolemia management in patients with type 2 diabetes. Am J Med 2002;112(8):603-609.

49. Leibson CL, Naessens JM, Brown RD, Whisnant JP. Accuracy of hospital discharge abstracts for identifying stroke. Stroke 1994;25(12):2348-2355.

50. Liu L, Reeder B, Shuaib A, Mazagri R. Validity of stroke diagnosis on hospital discharge records in Saskatchewan, Canada: implications for stroke surveillance. Cerebrovasc Dis 1999;9(4):224-230.

51. Piriyawat P, Smajsova M, Smith MA, Pallegar S, Al Wabil A, Garcia NM et al. Comparison of active and passive surveillance for cerebrovascular disease: The Brain Attack Surveillance in Corpus Christi (BASIC) Project. Am J Epidemiol 2002; 156(11):1062-1069.

52. Spolaore P, Brocco S, Fedeli U, Visentin C, Schievano E, Avossa F et al. Measuring accuracy of discharge diagnoses for a region-wide surveillance of hospitalized strokes. Stroke 2005; 36(5):1031-1034.

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CHAPTER �DIABETES AND CARDIOVASCULAR DISEASE IN ALBERTA

APPENDIX

Acute Coronary SyndromeDischarge Abstracts Database

D�agnos�s ICD-�-CM ICD-�0-CA

Acute.MI 410.X I21.X-I22.X

Unstable.Angina 411.X,.413.X I20.X,.I24.X

Alberta Physician Claims Data

Procedures Phys�c�an Cla�ms Data

PCI 51.59A,.51.59C,.51.59D,.51.59E,.51.59F

CABG 48.12,.48.12A,.48.13,.48.13A,.48.14,.48.14A,.48.15A,.48.15E,.48.15B,.48.15F,.48.15C,.48.15G,.48.15D

Heart Failure

Discharge Abstracts Database, Alberta Physician Claims Data, Ambulatory Care Classification System

ICD-�-CM ICD-�0-CA

Heart.Failure 428.X I50.X

Stroke

Discharge Abstracts Database, Alberta Physician Claims Data, Ambulatory Care Classification System

ICD-�-CM ICD-�0-CA

Stroke 430.X-438.X I60.X-I69.X,.G45.X

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ALBERTA DIABETES ATLAS 2007 ��

Peter A. Senior

M. Sean McMurtry

Ross T. Tsuyuki

Chapter � D�abetes and Lower L�mb Amputat�ons �n Alberta

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CHAPTER �

DIABETES AND LOWER LIMB AMPUTATIONS IN ALBERTA

KEY MESSAGES

• People with diabetes were 12 to 18 times more likely to have a lower limb amputation than people without diabetes.

• Younger adults with diabetes have significantly higher rates of lower limb amputation than their non-diabetic counterparts, compared to the oldest age groups.

• In people with diabetes, lower limb amputation is more common in the northern regions of Alberta compared to the southern regions.

BACKGROUND

Atherosclerotic peripheral arterial disease (PAD) and diabetic peripheral neuropathy (DPN) are serious complications of diabetes and can sometimes lead to lower limb problems (e.g., foot ulcers and amputations).(1) In people with diabetes, foot ulceration is usually a consequence of either; 1) impaired sensation which increases the risk of trauma, or 2) poor blood flow to the injured area which interferes with the healing process. Commonly both factors operate together. Susceptibility to injury and poor wound healing can lead to ulceration and unless treated promptly, foot ulcers may become infected particularly when diabetes control is poor. Soft tissue infection may progress to involve the underlying bone. These deeper infections are usually very difficult to treat and may require amputation. Similarly, when the extremities of the body are deprived of oxygen due to PAD, tissue death may result, leading to ulceration and/or gangrene. If revascularization is not possible and gangrene develops, amputation will usually be required. Lower limb problems are a major cause of morbidity and mortality in people with diabetes and contribute to increased healthcare costs.(2,3) Ulcers and amputations can be prevented by good foot care and prompt treatment of ulcers that are at their initial stage.(2)

Besides increased health care costs, people who have foot ulcers and/or lower limb amputations have a decreased health-related quality of life.(4,5) These individuals often have long treatment periods that can be both painful and time consuming with much time spent on clinic visits, hospitalization and frequent foot ulcer dressing changes with or without long term antibiotic therapy.(5) If a lower limb amputation results, patients are faced with many challenges such as needing assistance with activities of daily life.

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CHAPTER �DIABETES AND LOWER LIMB AMPUTATIONS IN ALBERTA

METHODS

Data from Alberta Health and Wellness (AHW) Physician Claims databases were utilized for these analyses. This dataset captures Alberta resident demographic information, and lower limb amputations with accompanying diagnostic information. Although there are other indicators of advanced PAD, such as foot ulceration and lower limb revascularization (e.g., peripheral angioplasty), we focused on lower limb amputations as a marker of DPN and/or end-stage of PAD in people with diabetes. We excluded lower limb amputations due to trauma and other specific causes, to focus our surveillance on amputations likely due to DPN and PAD (see Appendix for these codes). All adult residents of Alberta aged 20 years or greater were included in these analyses.

From these data, rates of lower limb amputation for those with and without diabetes were calculated. For each group, the number of people with amputations (numerator) was divided by the number of people in the province or region (denominator), respectively. Trends over time (1995-2005), as well as regional and age-specific rates for amputation were calculated. Persons with diabetes were identified as described in the Methods chapter. Due to the relatively low case counts for lower limb amputations within regions, we were unable to adjust for age and sex differences and therefore present only the case counts and crude rates in these findings.

FINDINGS

Lower limb amputation is a complication in people with diabetes that is rare in people without diabetes. During the past decade, people with diabetes were 12 to 18 times more likely to have a lower limb amputation than people without diabetes, after adjusting for age and sex (Figure 5.1). Amputation rates decreased over the years, however the ratio between those with and without diabetes remained constant. Lower limb amputation was about twice as common in males with diabetes than in females with diabetes (Figure 5.2).

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ALBERTA DIABETES ATLAS 2007 ��

DiabetesNo Diabetes

FemaleMale

30

25

20

15

10

5

0

5.1

Rat

e pe

r 10

,000

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

45

40

35

30

25

20

15

10

5

0

5.2

Rat

e pe

r 10

,000

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

DiabetesNo Diabetes

FemaleMale

30

25

20

15

10

5

0

5.1

Rat

e pe

r 10

,000

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

45

40

35

30

25

20

15

10

5

0

5.2

Rat

e pe

r 10

,000

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Figure 5.1 Age and Sex-Adjusted Lower L�mb Amputat�on Rates, ����-�00�

Figure 5.2 Age-Adjusted Lower L�mb Amputat�on Rates for Males and Females w�th D�abetes, ���� to �00�

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CHAPTER �DIABETES AND LOWER LIMB AMPUTATIONS IN ALBERTA

Rat

e pe

r 10

,000

60

50

40

30

20

10

0

5.4

Diabetes

No Diabetes

Diabetes

No Diabetes

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

0.30%

0.25%

0.20%

0.15%

0.10%

0.05%

0%

60

50

40

30

20

10

0

5.3

Perc

ent

with

One

or

Mor

e A

mpu

tatio

n

Rat

io (

Dia

bete

s: N

o D

ibet

es)

Age Group (Years)20-34 35-49 50-64 65-74 75+

Lower limb amputation is not common in young people without diabetes but becomes more common in older adults with and without diabetes (Figure 5.3). The rate ratio (or relative risk) demonstrates that the risk of lower limb amputation is much greater for adults with diabetes compared to those without diabetes. While there are more lower limb amputations in older patients, the relative risk of lower limb amputation is much higher in younger adults with diabetes compared to older adults. In fact, in the youngest age group of 20-34 years, those with diabetes are 48 times more likely to have a lower limb amputation than those without diabetes. In the age group 75 years and older, those with diabetes are only 5 times more likely to have a lower limb amputation than those without diabetes. The higher rate of amputation in older people is likely due to increased PAD in both groups. The excess of lower limb amputations in younger adults with diabetes is likely due to an excess of peripheral neuropathy rather then PAD alone.

Figure 5.3 Age-Spec�fic Lower L�mb Amputat�on Rates, �00�

There appears to be a north to south gradient in the rate of lower limb amputations among those with diabetes in Alberta (Figure 5.4). Those with diabetes who live in the Capital region and further north are all above the provincial average of 19.6 lower limb amputations per 10,000 persons in 2005.

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ALBERTA DIABETES ATLAS 2007 ��

Rat

e pe

r 10

,000

60

50

40

30

20

10

0

5.4

Diabetes

No Diabetes

Diabetes

No Diabetes

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

0.30%

0.25%

0.20%

0.15%

0.10%

0.05%

0%

60

50

40

30

20

10

0

5.3

Perc

ent

with

One

or

Mor

e A

mpu

tatio

n

Rat

io (

Dia

bete

s: N

o D

ibet

es)

Age Group (Years)20-34 35-49 50-64 65-74 75+

Figure 5.4 Crude Lower L�mb Amputat�on Rate by Reg�on, �00�

DISCUSSION

Foot ulcers and lower limb amputations cause a significant amount of morbidity in people with diabetes. The above findings stress the need for life-long surveillance of the diabetic foot at risk and the necessity of preventive foot care among diabetic patients.(3) Although the absolute numbers of people with diabetes that ultimately receive amputations are relatively small, the burden that lower limb amputation places on patients is very large. Also, due to the preventable nature of this complication, diabetic foot care is a very important aspect of the management of diabetes in Alberta. The rate of lower limb amputations has been suggested as an indicator of overall quality of care for diabetes.(6)

As previously noted, foot ulcers and lower limb amputations are a result of two different processes in people with diabetes. Decreased sensation due to diabetic peripheral neuropathy (nerve damage) makes it hard for people with diabetes to feel small cuts or damage to the foot; and poor blood flow to the legs and feet (peripheral arterial disease) prevents healing of these small cuts, allowing them to worsen. Diabetes itself, particularly if poorly controlled, increases the risk of ulcers becoming infected. Reducing the risk of lower limb amputations therefore requires multiple prevention strategies, including regular foot checks by the person with diabetes themselves, as well as by their health care providers.(2)

Poor blood circulation in the lower limbs is due to atherosclerosis, the same disease process that affects blood vessels of the heart (leading to heart attacks) and the brain (leading to stroke).(7,8) Atherosclerosis refers to the build up of cholesterol in the arteries, which over time leads to the narrowing of blood vessels that impairs blood supply. Reducing the risk of lower limb amputation therefore requires the same preventative treatment. Treatment includes cholesterol lowering, blood pressure lowering, anti-platelet (ASA) therapy and revascularization similar to that used to prevent and treat heart attacks and strokes.

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Unfortunately, there is evidence to suggest that people with diabetes and PAD are not optimally treated to reduce their risk of heart attacks or stroke.(9-11) Notably, lower limb amputation could be thought of as the “tip of the iceberg”, as it is a marker for end stages of DPN and PAD. There are a great deal many more patients with less severe (but still serious) forms of the disease who would benefit from better preventive therapies.

It is encouraging to see a steady reduction in the rate of lower limb amputations for Albertans with diabetes over the past decade. However, like other complications in people with diabetes, we observed considerable variation in the rate of lower limb amputations across the health regions of Alberta. It is not known why those living in central and northern Alberta have higher rates of lower limb amputation. Differences in these rates may reflect different levels of risk for people with diabetes in the regions, different use of preventive foot checks or risk-reducing drug therapy, access to health care providers, delay in seeking medical attention or in treating ulcers, or differences in the decision-making to undergo an amputation. As with many other trends observed in this Alberta Diabetes Atlas, further investigation is needed to better understand the reasons for the patterns, which may in turn lead to improvements in regional patient care.

References 1. Boyko EJ, Ahroni JH, Stensel V, Forsberg RC, Davignon DR, Smith DG. A prospective study of risk factors for diabetic foot

ulcer. The Seattle Diabetic Foot Study. Diabetes Care 1999;22(7):1036-42.

2. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. Canadian Diabetes Association 2003 clinical practice guidelines for the prevention and management of diabetes in Canada. Foot Care. Can J Diabetes 2003;27(suppl 2): S74-S75.

3. Reiber GE, Boyko EJ, Smith DG. Lower extremity foot ulcers and amputations in diabetes. In: Diabetes in America. 2nd ed. Bethesda, MD: National Diabetes Data Group, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; 1995:409-428.

4. Meatherall BL, Garrett MR, Kaufert J, et al. Disability and quality of life in Canadian aboriginal and non-aboriginal diabetic lower-extremity amputees. Arch Phys Med Rehabil 2005;86:1594-602.

5. Tennvall GR, Apelqvist J. Health-related quality of life in patients with diabetes mellitus and foot ulcers. Journal of Diabetes and Its Complications 2000;14:235-241.

6. Majumdar SR, Johnson JA, Bowker SL, Booth GL, Dolovich L, Ghali W, Harris SB, Hux JE, Holbrook A, Lee H, Toth EL, Yale J-F. A Canadian consensus for the standardized evaluation of quality improvement interventions in type 2 diabetes: Development of a Quality Indicator Set. Can J Diabetes 2005;29:220-229.

7. Beckman JA, Creager MA, and Libby P. Diabetes and atherosclerosis: Epidemiology, pathophysiology, and management. JAMA 2002;287:2570-2581.

8. Belch JJF, Topol EJ, Agnelli G, et al. Critical issues in peripheral arterial disease detection and management. Arch Intern Med 2003:163:884-892.

9. Hirsch AT, Criqui MH, Treat-Jacobson D, Regensteiner JG, Creager MA, Olin JW, Krook SH, Hunninghake DB, Comerota AJ, Walsh ME, McDermott MM, Hiatt WR. Peripheral arterial disease detection, awareness, and treatment in primary care. JAMA 2001;286:1317-24.

10. McGrae McDermott M, Hahn EA, Greenland P, et al. Atherosclerotic risk factor reduction in peripheral arterial disease: Results of a national physician survey. J Gen Intern Med 2002:17:895-904.

11. Brown LC, Johnson JA, Majumdar SR, Tsuyuki RT, McAlister FA. Evidence of sub-optimal cardiovascular risk management in patients with type 2 diabetes mellitus and symptomatic atherosclerosis. CMAJ 2004;171:1189-1192.

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ALBERTA DIABETES ATLAS 2007 ��

APPENDIX

Lower Limb AmputationAlberta Physician Claims data were used for these analyses. Every procedure is paired with a diagnostic code in the administrative databases; therefore any procedure code with one of the below diagnostic codes was excluded in order to focus our surveillance on amputations likely due to diabetic peripheral neuropathy and peripheral arterial disease.

D�agnos�s Procedure Code Descr�pt�on

Lower.Limb.Amputation 96.11A Amputation.and.disarticulation.of.one.toe

96.12A Amputation.and.disarticulation.of.foot:Metatarsal-.whole.ray

96.12B Amputation.and.disarticulation.of.foot:.Transmetatarsal

96.13 Amputation.and.disarticulation.of.ankle:.Symes,.Pirogoff

96.14 Amputation.of.lower.leg.below.knee

96.15 Amputation.of.thigh.or.disarticulation.of.knee:.Supracondylar.Thigh.through.femur

Excluded D�agnost�c Codes ICD-�-CM Descr�pt�on

170 Malignant.bone.tumor

171 Malignant.connective.tissue.tumor

213 Benign.neoplasm.of.bone

730 Osteomyelitis

740-759 Congenital.abnormalities

800-900 Trauma

901-904 Arterial.Injury

940-950 Burns

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ALBERTA DIABETES ATLAS 2007 ��

Chapter � D�abetes and K�dney D�sease �n Alberta

Scott Klarenbach

Marcello Tonelli

Brenda R. Hemmelgarn

Kailash K. Jindal

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CHAPTER �

DIABETES AND KIDNEY DISEASE IN ALBERTA

KEY MESSAGES

• The annual growth rate of end-stage renal disease in the diabetes population is more than double that of the non-diabetes population over the past decade.

• The proportion of patients with end-stage renal disease and diabetes has increased from 31% to 46% over the past decade.

• Steady incidence rates suggest the risk of end-stage renal disease is not increasing but the increasing number of people with diabetes is driving the increased prevalence of end-stage renal disease.

• The fraction of people with diabetes receiving a kidney transplant has increased from 25% in 1995 to 32% in 2005.

BACKGROUND

One of the most serious consequences of diabetes mellitus (DM) is renal or kidney disease, also known as diabetic nephropathy. This frequently progresses to end-stage renal disease (ESRD), a state where life-sustaining treatment of ongoing dialysis therapy (either hemodialysis or peritoneal dialysis) or kidney transplantation is necessary. Patients with DM are at an increased risk of developing ESRD, up to 13 times greater than those without DM.(1)

ESRD patients on dialysis have a very poor quality of life(2-5) and high mortality rates, with 5-year survival rates of less than 30%,(2) worse than many commonly occurring malignancies.(6) While kidney transplantation is the preferred treatment, the limited availability of organs has led to very long waiting list times.

Those with diabetes and ESRD have even poorer health outcomes than non-DM patients receiving dialysis. In addition to reporting a much lower quality of life,(7) persons with diabetes have significantly higher mortality. In Canada, the percentage of hemodialysis patients alive after three years was only 51% for those with DM, compared with 60% for those without DM.(8) Finally, patients with ESRD and DM tend to have more comorbid illnesses, such as cardiovascular and peripheral vascular disease, which may preclude treatment with kidney transplantation.

Provision of care to the ESRD population is associated with consumption of significant amounts of health care resources. In developed nations, it is estimated that ESRD affects only 0.07% of the population, but consumes 2-3% of health care budgets.(9-12)

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On a national level, the number of prevalent ESRD patients in Canada continues to grow at 6 to 13% per annum,(8,9,13) a rate which would be expected to result in a doubling of the ESRD population every 5-8 years. A significant contributor to the growth in ESRD patients is due to increased numbers of persons with DM. The fraction of persons who develop ESRD due to DM in Canada has increased from 25% to 34% from 1993 to 2002.(8)

Our objective was to describe the epidemiology of ESRD and kidney transplantation in Alberta from 1996 to 2005 with specific emphasis on patients with DM.

METHODS

Data from Alberta Health and Wellness (AHW), which provides health care insurance to all permanent residents of Alberta (including First Nations people), was utilized for this analysis. This administrative dataset captures demographic information, outpatient and inpatient encounters, and physician billing claims. All adult patients aged 20 or greater were included in these analyses.

Physician billing claim codes specific for the delivery of maintenance dialysis therapy over the study period (1996-2005) were used to identify dialysis patients (see Appendix). The patient population of interest were those receiving chronic dialysis, defined as having at least two dialysis billing codes in ≥ 90 days. The start date of dialysis was defined by the date of the earliest dialysis billing claim.

New or incident dialysis patients for a given year were defined if they met the above criteria, and if their start date of dialysis occurred in that year, without having been a dialysis case in the previous year. A person identified as an incident dialysis patient in a given year would be classified as a prevalent dialysis patient in subsequent years if additional dialysis billing claims occurred in these years. Due to changes in billing codes and practices during the time frame of this analysis, the type and location of dialysis modality was not assessed.

Kidney transplantation was identified by physician claims for the surgical procedure of kidney transplantation (see Appendix).

Persons with diabetes were identified as described in the Methods chapter. DM and ESRD status of individuals were determined for each year, then incidence and prevalence rates of ESRD were calculated for persons with and without DM for each year. Age-specific rates for ESRD and kidney transplantation are also reported.

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ALBERTA DIABETES ATLAS 2007 ��

Diabetes

No Diabetes

Total

6.2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

0

100

200

300

400

500

313296

353372

391423

478503

427

497

600

Num

ber

of C

ases

300

250

200

150

100

50

0

Year

6.1

Rat

e pe

r 10

0,00

0

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Diabetes

No Diabetes

FINDINGS

IncidenceThe age and sex-adjusted rate of ESRD per 100,000 persons was relatively stable for persons with and without DM over the decade of observation. The rate of developing ESRD for those with DM has been 11 to 15 times higher compared to those without DM (Figure 6.1).

The number of all incident ESRD cases per year increased from 313 to 497 over ten years (Figure 6.2), with an average annual growth of 5.8%. Over the same time frame, the average annual ESRD growth for persons with DM was 9.4%, compared with 3.7% for those without DM. In 1996, 35% of all the incident ESRD cases had DM. This figure increased to nearly 50% in 2005 (Figure 6.3).

For the year 2005, the 50-64 and 65-74 age groups contributed the most number of new patients (Figure 6.4). These two age groups also had the highest number of patients with DM, outnumbering new patients with ESRD without DM. The greatest average annual growth rate over the ten year period of observation was in patients with DM in the three oldest age groups, with growth rates of 2 to 4 fold greater than those without DM (Figure 6.5).

Figure 6.1 Age and Sex-Adjusted ESRD Inc�dence Rates, ����-�00�

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CHAPTER �DIABETES AND KIDNEY DISEASE IN ALBERTA

Diabetes

No Diabetes

Total

6.2

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

0

100

200

300

400

500

313296

353372

391423

478503

427

497

600

Num

ber

of C

ases

300

250

200

150

100

50

0

Year

6.1

Rat

e pe

r 10

0,00

0

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Diabetes

No Diabetes

6.4

20-34 35-49 50-64 65-74 75+

Age Group (Years)

90

80

70

60

50

40

30

20

10

0

Num

ber

of C

ases

Inci

dent

Cas

es (

Perc

enta

ge)

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

6.3

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

Diabetes

No Diabetes

Diabetes

No Diabetes

Figure 6.2 Inc�dent ESRD Cases, ����-�00�

Figure 6.3 Inc�dent ESRD Cases, ����-�00�

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ALBERTA DIABETES ATLAS 2007 ��

6.4

20-34 35-49 50-64 65-74 75+

Age Group (Years)

90

80

70

60

50

40

30

20

10

0

Num

ber

of C

ases

Inci

dent

Cas

es (

Perc

enta

ge)

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

6.3

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

Diabetes

No Diabetes

Diabetes

No Diabetes

6.5

20-34 35-49 50-64 65-74 75+

Age Group (Years)

20%

18%

16%

14%

12%

10%

8%

6%

4%

2%

0%

Ave

rage

Ann

ual G

row

th (

Perc

enta

ge)

600

500

400

300

200

100

0

Year

6.6

Rat

e pe

r 10

0,00

0

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Diabetes

No Diabetes

Diabetes

No Diabetes

Figure 6.4 Age-Spec�fic Inc�dent ESRD Cases, �00�

Figure 6.5 Average Annual Growth of Inc�dent ESRD Cases, ����-�00�

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CHAPTER �DIABETES AND KIDNEY DISEASE IN ALBERTA

6.5

20-34 35-49 50-64 65-74 75+

Age Group (Years)

20%

18%

16%

14%

12%

10%

8%

6%

4%

2%

0%

Ave

rage

Ann

ual G

row

th (

Perc

enta

ge)

600

500

400

300

200

100

0

Year

6.6

Rat

e pe

r 10

0,00

0

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Diabetes

No Diabetes

Diabetes

No Diabetes

PrevalenceThe age and sex-adjusted rate per 100,000 persons with ESRD requiring dialysis was 10 to 12 times higher for patients with DM compared with those without DM from the years 1996 to 2005 (Figure 6.6). The number of patients with ESRD on dialysis increased from 910 to 1834 from 1996 to 2005, with an annual average growth of 8.1% (Figure 6.7). The average annual growth rate for persons with DM and ESRD was 13.0%, compared with 5.2% of those with ESRD without DM. The proportion of patients with ESRD and DM has increased from 31% to 46% over the period of observation (Figure 6.8).

Kidney transplantationKidney transplantation was more common in patients aged 64 or less (Figure 6.9). The fraction of persons with DM receiving a kidney transplant has increased from 25% in 1995 to 32% in 2005 (Figure 6.10).

Figure 6.6 Age and Sex-Adjusted ESRD Prevalence Rates, ����-�00�

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ALBERTA DIABETES ATLAS 2007 ��

6.7

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Num

ber

of C

ases

Prev

alen

t C

ases

(Pe

rcen

tage

)

9101004

11021196

1284

1395

1553

17021766

1834

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

6.8

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

Diabetes

No Diabetes

Diabetes

No Diabetes

Total

6.7

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Num

ber

of C

ases

Prev

alen

t C

ases

(Pe

rcen

tage

)

9101004

11021196

1284

1395

1553

17021766

1834

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

6.8

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005Year

Diabetes

No Diabetes

Diabetes

No Diabetes

Total

Figure 6.7 Prevalent ESRD Cases, ����-�00�

Figure 6.8 Prevalent ESRD Cases, ����-�00�

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CHAPTER �DIABETES AND KIDNEY DISEASE IN ALBERTA

6.9

35

30

25

20

15

10

5

0

Num

ber

of C

ases

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

Diabetes

No Diabetes

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Kid

ney

Tra

nspl

anta

tion

Cas

es (

Perc

enta

ge)

6.9

35

30

25

20

15

10

5

0

Num

ber

of C

ases

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

Diabetes

No Diabetes

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Kid

ney

Tra

nspl

anta

tion

Cas

es (

Perc

enta

ge)

Figure 6.9 Age-Spec�fic K�dney Transplantat�on Cases, �00�

Figure 6.10 K�dney Transplantat�on Cases, ����-�00�

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ALBERTA DIABETES ATLAS 2007 ��

DISCUSSION

Over the past decade, the number of patients with DM who developed ESRD annually, or who are currently receiving dialysis therapy in a given year, have increased at an alarming rate in Alberta. Patients with DM now account for almost half of the new and existing patients on dialysis, a grave concern given the poor outcomes commonly seen for these patients.

The relative stability of incidence and prevalence rates when adjusted for age and sex suggest that this growth trend may not be due to a higher risk of developing ESRD in patients with DM, but instead may indicate that the number of persons with DM is increasing, which is supported by other data in this Atlas (see Epidemiological Trends chapter).

The age groups 50 years and older have the highest number of patients with incident ESRD and DM; the greatest growth in incident ESRD is seen in those over the age of 75. To some extent this may be due to improvements in dialysis technology, such that patients with a heavy burden of disease (such as the elderly with DM) may now be candidates for dialysis, or that people with DM live longer and thus have a greater likelihood of developing ESRD. However, the shift in the Alberta demographic distribution resulted in a higher proportion of older people whose risk of developing DM is probably a much more important factor, especially over the past 5 years.

Therapy exists for patients with kidney complications of diabetes to delay or prevent the progression to ESRD. While it is encouraging that the age and sex-adjusted rates of new cases of ESRD in those with DM appears to be trending downward, increasing the use of proven prevention efforts remain an important goal.

While use of administrative data provides a population-based method of obtaining disease trends, it also has limitations. Given our definition of chronic dialysis, patients with ESRD who die within 90 days of initiation of treatment will not be captured. We also identified all patients with ESRD, although DM may not have been the cause of ESRD. Given limitations in data and billing codes, we were unable to look at home-based compared to in-hospital dialysis. In this initial surveillance of DM and ESRD, we did not assess ESRD-related mortality; this will be included in future versions of the Alberta Diabetes Atlas.

While the fraction of persons with DM receiving a kidney transplant has increased over the last decade, it does not appear to have kept pace with the increase of ESRD incidence in patients with DM. This may be due to various factors including decreased eligibility for kidney transplantation due to concomitant comorbid illness or advanced age, and the greater risk of mortality while patients are on the transplant wait list. More research is needed to confirm these speculations.

In light of poor patient outcomes, high health care costs and continued growth in patient numbers, kidney disease due to diabetes is an emerging public health issue in Canada and worldwide. Continued efforts to identify patients at risk and institute therapy to slow the progression of diabetic nephropathy to ESRD is warranted to attenuate the impact of this complication.

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CHAPTER �DIABETES AND KIDNEY DISEASE IN ALBERTA

APPENDIX

Alberta Physician Claims Data

Procedure Code Descr�pt�on

Peritoneal.dialysis 13.99C Assessment.and.management.of.an.unstable.patient.with.acute/chronic.renal.failure.treated.by.peritoneal.dialysis

13.99D Assessment.and.management.of.a.stable.patient.with.chronic.renal.failure.treated.by.peritoneal.dialysis

Hemodialysis 13.99A Hemodialysis.treatment,.unstable.patient

13.99B Hemodialysis.treatment,.stable.patient

Home.based.or.satellite.therapy.

13.99O Management.of.dialysis.patients.on.home.dialysis.or.receiving.treatment.in.a.remote.hemodialysis.unit.(per.week)

Kidney.Transplantation 67.59A Renal.transplant.(homo,.hetero,.auto)

References 1. Brancati FL, Whelton PK, Randall BL, Neaton JD, Stamler J, Klag MJ. Risk of end-stage renal disease in diabetes mellitus: a

prospective cohort study of men screened for MRFIT. Multiple Risk Factor Intervention Trial. JAMA 1997;278:2069-2074.

2. USRDS: the United States Renal Data System. Am J Kidney Dis. 2003;42:1-230.

3. Fukuhara S, Lopes AA, Bragg-Gresham JL, et al. Health-related quality of life among dialysis patients on three continents: the Dialysis Outcomes and Practice Patterns Study. Kidney Int. 2003;64:1903-1910.

4. Gokal R. Quality of life in patients undergoing renal replacement therapy. Kidney Int Suppl. 1993;40:S23-7.

5. Manns B, Johnson JA, Taub K, Mortis G, Ghali WA, Donaldson C. Quality of life in patients treated with hemodialysis or peritoneal dialysis: what are the important determinants? Clin Nephrol. 2003;60:341-351.

6. Kiberd BA, Clase CM. Cumulative risk for developing end-stage renal disease in the US population. J Am Soc Nephrol. 2002;13:1635-1644.

7. Parsons DS, Harris DC. A review of quality of life in chronic renal failure. Pharmacoeconomics 1997;12:140-160.

8. Canadian Organ Replacement Register. Preliminary Report for Dialysis and Transplantation 2002. Canadian Institute for Health Information. 2003

9. Alberta Health and Wellness, Province Wide Services Working Group. 2003 Province Wide Services Annual Report on Activities and Outcomes. 2004; July (Accessed June 2005)

10. Garella S. The costs of dialysis in the USA. Nephrol Dial Transplant. 1997;12 Suppl 1:10-21.

11. Tomson CR. Recent advances: nephrology. BMJ. 2000;320:98-101.

12. Mallick NP. The costs of renal services in Britain. Nephrol Dial Transplant. 1997;12 Suppl 1:25-28.

13. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases B, MD. U.S. Renal Data System, USRDS 2002 Annual Data Report: Atlas of End-Stage Renal Disease in the United States, 2002

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ALBERTA DIABETES ATLAS 2007 ��

Chapter � D�abetes and Eye D�sease �n Alberta

Matthew T. S. Tennant

Christopher J. Rudnisky

Jeffrey A. Johnson

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ALBERTA DIABETES ATLAS 2007 ��

CHAPTER �

DIABETES AND EYE DISEASE IN ALBERTA

KEY MESSAGES

• Only 60% of people with diabetes have had an eye examination by an ophthalmologist within 3 years after identification of their diabetes.

• Younger people with diabetes are less likely to have an eye examination by an ophthalmologist.

• Treatments for diabetic retinopathy, including laser photocoagulation and vitrectomy, have increased substantially in the past decade.

• Other forms of eye disease, including cataracts and glaucoma, are 1.5 to 2 times more likely for people with diabetes.

• People with diabetes in Palliser Region have higher rates of eye examinations and 2 to 4 times higher rate of photocoagulation compared to all other regions.

BACKGROUND

Diabetic retinopathy (DR) is an important and common complication of diabetes,(1-4) and an important cause of vision loss in Canada.(5) As the prevalence of diabetes increases within the Canadian population,(6-8) it is expected that blindness due to diabetic retinopathy will also increase. Screening and treatment of DR have been shown to be cost-effective methods to reduce vision loss.(9, 10) However, despite the proven benefits of screening, many Canadians with diabetes do not receive an annual dilated eye examination as recommended by the Diabetes Clinical Practice Guidelines (2003).

The prevalence of DR is associated with the severity of diabetes (e.g., glycemic control) as well as duration of disease. The risk of DR is reduced by well controlled blood glucose and blood pressure, while the risk increases with duration of disease.(11-13) Treatment of DR includes laser photocoagulation and vitrectomy, both of which aim to reduce the risk of moderate or severe vision loss.

Screening for DR in people who have diabetes is effective at identifying treatable disease.(14) In Canada, the current standard of care for DR screening is a stereoscopic assessment of the retina through a dilated pupil by an experienced professional. The timing of a screening examination varies depending on the type of diabetes. In type 1 diabetes, an eye examination should be performed within 5 years of diagnosis after the age of 15, and on annual basis thereafter. In type 2 diabetes, an eye examination should be performed at the time of diagnosis, and then on an annual basis.(15)

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

In addition to retinopathy, people with diabetes also have an increased risk of glaucoma and cataracts which contribute to an increased risk of vision loss. Glaucoma can be treated with eye drops and medications, but in some cases will require surgical correction to reduce pressure in the eye. Cataracts also interfere with vision and can be surgically removed if necessary.

METHODS

Data from Alberta Health and Wellness (AHW) Physician Claims databases were utilized for this analysis. This dataset captures Alberta resident demographic information, eye disease visits and procedures completed in an inpatient or outpatient environment. The dataset also captures all contacts with ophthalmologists. All adult patients aged 20 or greater were included in the analyses.

Ophthalmology billing claim codes specific for the procedures of retinal laser treatment, vitrectomy, cataract surgery and glaucoma surgery (see Appendix) over the study period (1995-2005) were reported. The Canadian Diabetes Association Clinical Practice Guidelines recommend screening for diabetic retinopathy by an experienced eye professional.(15) In addition to ophthalmologists, optometrists also perform eye exams. Since optometrists have a different billing system and do not consistently bill AHW for their services, only a small proportion of the eye examinations performed would be captured. It is probable that a subset of people with diabetes have been assessed by an optometrist in this same time period; however the exact percentage assessed in this manner is unknown. We therefore only included eye examinations by an ophthalmologist in our analyses.

In order to calculate the incidence of an ophthalmology exam after initial identification of diabetes, all contacts with an ophthalmologist within one, two and three years were reported.

Rates of eye disease procedures for those with and without diabetes were also calculated. For each group, the number of people with eye disease procedures (numerator) was divided by the total number of people in the province or region (denominator), respectively.

Persons with incident and prevalent diabetes were identified as described in the Methods chapter. As with other rates in the Atlas, we used a direct standardization to age and sex adjust rates of eye examinations and procedures, using the Alberta population according to the 2001 Canadian Census. Due to the small number of cases per region, we present the crude rates for procedures when comparing health regions.

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ALBERTA DIABETES ATLAS 2007 ��

Rat

e pe

r 10

0

Diabetes

No Diabetes

35

30

25

20

15

10

5

0

7.1

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

Female

Male

50

45

40

35

30

25

20

15

10

5

0

7.2

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

0

FINDINGS

Eye ExaminationsOver the past decade, people with diabetes were more than twice as likely to have an eye examination performed by an ophthalmologist compared to people without diabetes. Still, despite this higher rate, only one-quarter to one-third of those with diabetes had a yearly eye examination by an ophthalmologist in the past decade. Figure 7.1 illustrates that since 2001 there is actually a decreasing trend of eye exams being performed among those with and without diabetes.

Figure 7.1 Age and Sex-Adjusted Rates of Eye Exam�nat�on by an Ophthalmolog�st, ����-�00�

Older people with diabetes had higher rates of eye examinations (Figure 7.2). In 2005, men had more eye examinations by an ophthalmologist compared to females when less than 49 years of age, but the opposite was true from ages 50 to 74.

The overall provincial rate of eye examinations by an ophthalmologist among those with and without diabetes in 2005 was 8.9%. After adjusting for differences in age, the rate of an eye examination by an ophthalmologist for people with and without diabetes varied considerably between health regions. In the Palliser region, 41% of those with diabetes were examined by an ophthalmologist, versus only 16 % in the Northern Lights Health Region (Figure 7.3). In every health region, however, those who have diabetes had much higher rates of eye exam compared to those without diabetes.

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

Rat

e pe

r 10

0

Diabetes

No Diabetes

35

30

25

20

15

10

5

0

7.1

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

Female

Male

50

45

40

35

30

25

20

15

10

5

0

7.2

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

0

7.3

Rat

e pe

r 10

0

Diabetes

No Diabetes

50

45

40

35

30

25

20

15

10

5

0Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

70%

60%

50%

40%

30%

20%

10%

0%

7.4

0 years 2 years 3 years1 years

Time from Initial Identification of Diabetes

Cas

es w

ith a

t Le

ast

One

Eye

Exa

m (

Perc

enta

ge)

Figure 7.2 Age-Spec�fic Rates of Eye Exam�nat�on by an Ophthalmolog�st �n People w�th D�abetes, �00�

Figure 7.3 Age-Adjusted Rates of Eye Exam�nat�on by an Ophthalmolog�st by Reg�on, �00�

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

ALBERTA DIABETES ATLAS 2007 �0�

7.3

Rat

e pe

r 10

0

Diabetes

No Diabetes

50

45

40

35

30

25

20

15

10

5

0Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

70%

60%

50%

40%

30%

20%

10%

0%

7.4

0 years 2 years 3 years1 years

Time from Initial Identification of Diabetes

Cas

es w

ith a

t Le

ast

One

Eye

Exa

m (

Perc

enta

ge)

In Alberta, the incidence of an eye examination by an ophthalmologist within 3 years of identification of diabetes has been low. Between 1995 and 2004, approximately 60% of people had been assessed by an ophthalmologist within 3 years of being identified with diabetes (Figure 7.4).

Figure 7.4 Cumulat�ve Inc�dence of Eye Exam�nat�on by an Ophthalmolog�st w�th�n the F�rst � Years after Ident�ficat�on of D�abetes (����-�00�)

When stratified by age, older people (75+ years) are more likely to have undergone an eye examination within 3 years of identification of diabetes than younger people (Figure 7.5). Females with diabetes are less likely to have an eye exam by an ophthalmologist when they are 20-49 years old, but are slightly more likely to have an eye exam in the older age groups (50+ years) compared to their diabetic male counterparts.

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

7.6

Year 1

Year 2

Year 3

Year 1

Year 2

Year 3

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

80%

70%

60%

50%

40%

30%

20%

10%

0%

7.5

35-49 50-6420-34 65-74 75+ OverallAge Group (Years)

OverallFemale Male OverallFemale Male OverallFemale Male OverallFemale Male OverallFemale Male OverallFemale Male

Cas

es w

ith a

t Le

ast

One

Eye

Exa

m (

Perc

enta

ge)

Cas

es w

ith a

t Le

ast

One

Eye

Exa

m (

Perc

enta

ge)

7.6

Year 1

Year 2

Year 3

Year 1

Year 2

Year 3

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

80%

70%

60%

50%

40%

30%

20%

10%

0%

7.5

35-49 50-6420-34 65-74 75+ OverallAge Group (Years)

OverallFemale Male OverallFemale Male OverallFemale Male OverallFemale Male OverallFemale Male OverallFemale Male

Cas

es w

ith a

t Le

ast

One

Eye

Exa

m (

Perc

enta

ge)

Cas

es w

ith a

t Le

ast

One

Eye

Exa

m (

Perc

enta

ge)

Figure 7.5 Cumulat�ve Inc�dence of Eye Exam�nat�on by an Ophthalmolog�st �-� Years after Ident�ficat�on of D�abetes (����-�00�)

While there was considerable regional variation in the rate of eye examination by an ophthalmologist, people with diabetes showed similar patterns in the frequency of having such an eye exam following identification of diabetes. In the Northern Lights Region, only 33% of people had an eye examination within 3 years of their diabetes diagnosis. This contrasts with Palliser where 76% of people had an eye examination within 3 years of being identified with diabetes (Figure 7.6).

Figure 7.6 Cumulat�ve Inc�dence of Eye Exam�nat�on by an Ophthalmolog�st �-� Years after Ident�ficat�on of D�abetes, by Reg�on (����-�00�)

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

ALBERTA DIABETES ATLAS 2007 �0�

Rat

e pe

r 10

,000

Diabetes

No Diabetes

180

160

140

120

100

80

60

40

20

0

7.7

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

250

200

150

100

50

0

7.8

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

,000

Diabetes

No Diabetes

Retinal PhotocoagulationThe age-adjusted rate of retinal photocoagulation for people with diabetes is over 20 times higher than for those without diabetes. There was a marked increase in the rate of retinal photocoagulation in Alberta from 1997 to 2001, although the rate has leveled off in more recent years (Figure 7.7).

Figure 7.7 Age-Adjusted Rates of Ret�nal Laser Treatment, ����-�00�

Retinal photocoagulation is much more common for people with diabetes at all ages, but the difference in rates between people with diabetes and without diabetes is much greater in the younger age groups. With advancing age, other eye diseases necessitating laser treatment such as retinal tear, retinal detachment or retinal vein occlusion are more common. This is reflected with the higher rates of retinal photocoagulation for non-diabetic people over 75 years of age (Figure 7.8).

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

Rat

e pe

r 10

,000

Diabetes

No Diabetes

180

160

140

120

100

80

60

40

20

0

7.7

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

250

200

150

100

50

0

7.8

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

,000

Diabetes

No Diabetes

7.9

Rat

e pe

r 10

,000

Diabetes

No Diabetes

Rat

e pe

r 10

,000

Diabetes

No Diabetes

60

50

40

30

20

10

0

7.10

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

500

450

400

350

300

250

200

150

100

50

0Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

Figure 7.8 Age-Spec�fic Rates of Ret�nal Laser Treatment, �00�

The rate of retinal photocoagulation was relatively uniform for most health regions in Alberta in 2005, with the exception of Palliser Health Region (Figure 7.9). People with diabetes in the Palliser Health Region were 2 to 4 times more likely to have retinal photocoagulation than in any other health region in the province.

Figure 7.9 Crude Rates of Ret�nal Laser Treatment by Reg�on, �00�

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

ALBERTA DIABETES ATLAS 2007 �0�

7.9

Rat

e pe

r 10

,000

Diabetes

No Diabetes

Rat

e pe

r 10

,000

Diabetes

No Diabetes

60

50

40

30

20

10

0

7.10

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

500

450

400

350

300

250

200

150

100

50

0Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

Vitrectomy Surgery Vitrectomy is a surgical procedure that is used to treat advanced DR, as well as other forms of eye disease. When performed, it suggests that other less invasive treatment options have failed. The age adjusted rate for vitrectomy surgery for people with diabetes is at least 6 times higher than for those without diabetes (Figure 7.10). We observed an increase in the rate of vitrectomy surgery in the late 1990’s, peaking in 2001-2003.

Figure 7.10 Age-Adjusted Rates of V�trectomy, ����-�00�

Although vitrectomy surgery is relatively common for people with diabetes between the ages of 20 and 50, vitrectomy surgery for other non-diabetic retinal diseases is age dependent, with a much higher rate for people over 75 years of age (Figure 7.11).

The rates of vitrectomy surgery for people with and without diabetes were relatively similar across the health regions in 2005; the rates for people with diabetes was uniformly much higher than for people without diabetes (Figure 7.12).

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

7.12

Rat

e pe

r 10

,000

Diabetes

No Diabetes

90

80

70

60

50

40

30

20

10

0Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

Diabetes

No Diabetes

80

70

60

50

40

30

20

10

0

7.11

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

,000

7.12

Rat

e pe

r 10

,000

Diabetes

No Diabetes

90

80

70

60

50

40

30

20

10

0Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

Diabetes

No Diabetes

80

70

60

50

40

30

20

10

0

7.11

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

,000

Figure 7.11 Age-Spec�fic Rates of V�trectomy, �00�

Figure 7.12 Crude Rates of V�trectomy by Reg�on, �00�

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ALBERTA DIABETES ATLAS 2007 �0�

Rat

e pe

r 10

,000

Diabetes

No Diabetes

140

120

100

80

60

40

20

0

7.13

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

Diabetes

No Diabetes

700

600

500

400

300

200

100

0

7.14

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

,000

Rat

e pe

r 10

,000

Diabetes

No Diabetes

140

120

100

80

60

40

20

0

7.13

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

Diabetes

No Diabetes

700

600

500

400

300

200

100

0

7.14

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

,000

Cataract SurgeryThe age-adjusted rates for cataract surgery for people with diabetes were almost double that of people without diabetes. This has remained fairly stable over the past decade (Figure 7.13).

Figure 7.13 Age-Adjusted Rates of Cataract Surgery, ����-�00�

Although cataract surgery is more common in people with diabetes compared to people without diabetes, age appears to be the primary risk factor that leads to cataract surgery (Figure 7.14).

Figure 7.14 Age-Spec�fic Rates of Cataract Surgery, �00�

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

Rat

e pe

r 10

,000

Diabetes

No Diabetes

9

8

7

6

5

4

3

2

1

0

7.16

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

7.15

Rat

e pe

r 10

,000

Diabetes

No Diabetes

400

350

300

250

200

150

100

50

0Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

The rate of cataract surgery for people with and without diabetes did not vary much between health regions in 2005; the rate for people with diabetes was uniformly higher than for people without diabetes. Northern Lights Health Region had the lowest rate of cataract surgery for people with diabetes (Figure 7.15). After adjusting for differences in age, the differences across region were reduced.

Figure 7.15 Crude Rates of Cataract Surgery by Reg�on, �00�

Glaucoma SurgeryThe age-adjusted rates for glaucoma surgery for people with diabetes were more than double that of people without diabetes (Figure 7.16). It appears that the overall rate of glaucoma surgery has decreased from 1995 and 1996, to a more steady level in the past 8 years. Open angle glaucoma is diagnosed and treated more often at a younger age in people with diabetes which is reflected by larger differences between those with diabetes and those without. The rates of glaucoma surgery for those with and without diabetes in the older age groups are more similar (Figure 7.17). Due to the small number, we have not reported rates of glaucoma surgery by region.

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ALBERTA DIABETES ATLAS 2007 �0�

Rat

e pe

r 10

,000

Diabetes

No Diabetes

9

8

7

6

5

4

3

2

1

0

7.16

1996 19971995 1998 1999 2000 2001 2002 2003 2004 2005

Year

7.15

Rat

e pe

r 10

,000

Diabetes

No Diabetes

400

350

300

250

200

150

100

50

0Chinook Palliser Calgary David

ThompsonEast Central Capital Aspen Peace

CountryNorthern

LightsRegion

Diabetes

No Diabetes

16

14

12

10

8

6

4

2

0

7.17

35-49 50-6420-34 65-74 75+

Age Group (Years)

Rat

e pe

r 10

,000

Figure 7.16 Age-Adjusted Rates of Glaucoma Surgery, ����-�00�

Figure 7.17 Age-Spec�fic Rates of Glaucoma Surgery, �00�

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

DISCUSSION

Diabetic retinopathy is a preventable cause of blindness in Alberta. Timely treatment, in the form of laser photocoagulation or vitrectomy surgery, can reduce the risk of vision loss. Screening, in the form of a retinal examination through a dilated pupil, is the most important first step in preventing an epidemic of blindness. On average, however, only two thirds of Albertans receive an eye examination by an ophthalmologist within three years of identification of diabetes, a rate that needs to be targeted for improvement by government, health care providers and eye care professionals.(15) The long-term economic and social benefits realized by reducing blindness and ocular morbidity would offset any short-term costs associated with improved screening programs.

There were notable trends in the rates of photocoagulation and vitrectomy over the past decade, with an increase in these procedures in late 1999 to 2002. These changes in rates likely represent increased access to these services, with new ophthalmologists joining the province in 1999-2000. In more recent years, there has been a decrease in the rate of these procedures. This information highlights the importance of access to specialty care for people with diabetes, and the sensitivity of the Alberta Diabetes Surveillance System to capture changes in availability of specialist care.

One limitation in using only Alberta Health and Wellness administrative data for reporting on eye disease in Alberta is that optometrists also perform eye exams. Optometry, however, has a different billing system. Since they do not consistently bill Alberta Health and Wellness for their services, only a small proportion of the eye exams that optometrists perform would be captured.

In addition to retinopathy, other forms of eye disease are also more common in people with diabetes. Our data suggests that cataract formation occurs more often and at a younger age in people with diabetes. Contributing to this increased rate of cataract formation may be that both laser photocoagulation and vitrectomy surgery increase the risk of developing cataracts. As well, although glaucoma is more common in people with diabetes, age appears to be an important risk factor associated with glaucoma surgery. Glaucoma surgery does appear to be much more common in young people with diabetes, perhaps reflecting the treatment of neovascular glaucoma due to advanced diabetic retinopathy. Another possibility is that the treatment of diabetic retinopathy itself, such as vitrectomy, leads to post-operative intraocular pressure rises that are not controllable with medications alone, thus an indication for glaucoma surgery.

The regional variation in rates of eye examination by an ophthalmologist and rates of photocoagulation are also notable findings. In 2005, people with diabetes in Palliser were 2 to 4 times more likely to have photocoagulation than people with diabetes in other health regions, even after adjusting for differences in age between regions. It is not clear why Palliser has this high rate of photocoagulation, as the rates of cataract surgery and vitrectomy within this health region are similar to other health regions across the province. Further evaluation of the data is needed to help define the reasons behind this anomaly.

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ALBERTA DIABETES ATLAS 2007 ���

References 1. Roy MS, Klein R, O’Colmain BJ, et al. The prevalence of diabetic retinopathy among adult type 1 diabetic persons in the

United States. Arch Ophthalmol 2004;122(4):546-51.

2. Klein R, Klein BE, Moss SE, Cruickshanks KJ. The Wisconsin Epidemiologic Study of Diabetic Retinopathy: XVII. The 14-year incidence and progression of diabetic retinopathy and associated risk factors in type 1 diabetes. Ophthalmology 1998;105(10):1801-15.

3. Klein R, Klein BE, Moss SE, et al. The Wisconsin epidemiologic study of diabetic retinopathy. III. Prevalence and risk of diabetic retinopathy when age at diagnosis is 30 or more years. Arch Ophthalmol 1984;102(4):527-32.

4. Klein R, Klein BE, Moss SE, et al. The Wisconsin epidemiologic study of diabetic retinopathy. II. Prevalence and risk of diabetic retinopathy when age at diagnosis is less than 30 years. Arch Ophthalmol 1984;102(4):520-6.

5. Maberley DA, Hollands H, Chuo J, et al. The prevalence of low vision and blindness in Canada. Eye 2006;20(3):341-6.

6. Seidell JC. Obesity, insulin resistance and diabetes--a worldwide epidemic. Br J Nutr 2000;83 Suppl 1:S5-8.

7. Young TK, Reading J, Elias B, O’Neil JD. Type 2 diabetes mellitus in Canada’s first nations: status of an epidemic in progress. CMAJ 2000;163(5):561-6.

8. Tan MH, MacLean DR. Epidemiology of diabetes mellitus in Canada. Clin Invest Med 1995;18(4):240-6.

9. Javitt JC. Cost savings associated with detection and treatment of diabetic eye disease. Pharmacoeconomics 1995;8 Suppl 1:33-9.

10. Javitt JC, Aiello LP. Cost-effectiveness of detecting and treating diabetic retinopathy. Ann Intern Med 1996;124(1 Pt 2):164-9.

11. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. The Diabetes Control and Complications Trial Research Group. N Engl J Med 1993;329(14):977-86.

12. Efficacy of atenolol and captopril in reducing risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 39. UK Prospective Diabetes Study Group. BMJ 1998;317(7160):713-20.

13. Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38. UK Prospective Diabetes Study Group. BMJ 1998;317(7160):703-13.

14. Fundus photographic risk factors for progression of diabetic retinopathy. ETDRS report number 12. Early Treatment Diabetic Retinopathy Study Research Group. Ophthalmology 1991;98(5 Suppl):823-33.

15. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. Canadian Diabetes Association 2003 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. Can J Diabetes 2003;27(suppl 2):[S76-S80].

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CHAPTER �DIABETES AND EYE DISEASE IN ALBERTA

APPENDIX

Examination by an Ophthalmologist Defined as any visit by an individual claimed by an Ophthalmologist.

Alberta Physician Claims Data

Procedures: Code Descr�pt�on

Retinal.Photocoagulation.

28.5A Light.coagulation.or.cryopexy.–.(treatment.of.lesions.of.retina.or.choroid)

Vitrectomy.Surgery 28.72A Aspiration/washout.of.vitreous.cavity.with.replacement

28.72B Total.vitrectomy

28.74A Discission.of.vitreous/retinal.adhesions

28.74B Stripping.of.premacular.membrane,.associated.vitrectomy.and.retinal.encircling

Cataract.Surgery 27.72 Insertion.of.intraocular.lens.prosthesis.with.cataract.extraction,.one-stage

Glaucoma.Surgery 26.2A Glaucoma..(all.major.operations).except.laser

26.2B Glaucoma.implant.procedures.with.reservoir

26.25A Repeat.trabeculectomy

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ALBERTA DIABETES ATLAS 2007 ���

Lauren C. Brown

Larry W. Svenson

Cynthia A. Beck

Chapter � D�abetes and Mental Health D�sorders �n Alberta

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ALBERTA DIABETES ATLAS 2007 ���

CHAPTER �

DIABETES AND MENTAL HEALTH DISORDERS IN ALBERTA

KEY MESSAGES

• The prevalence of mental health conditions have increased in the diabetes population in the past decade and are much more prevalent than in the non-diabetes population.

• Affective and anxiety disorders are most common in younger adults with diabetes.

• Psychotic disorders, due to either organic or non-organic causes, are more common in diabetes across all age groups.

BACKGROUND

Mental illness is increasingly being recognized as an important comorbidity in people with diabetes. Previous research has demonstrated an increased risk of type 2 diabetes in people with a history of depression or depressive symptomatology.(1-4) In a Canadian context, data from the province of Saskatchewan demonstrated an increased risk of type 2 diabetes in people with depression.(1) Similarly, schizophrenia is considered a risk factor for many chronic medical conditions including diabetes. The Canadian Diabetes Association lists schizophrenia as a risk factor for diabetes;(5) and observational studies have found the prevalence of diabetes to be 2 to 3 times higher in individuals with schizophrenia compared to the general population.(5,6) The mechanism behind the increased risk of diabetes in people with mental illness is unclear, but may be related to a combination of biochemical changes or behavioral symptoms, or even may be due to the medications used to treat mental illness.(7-9)

The combination of comorbid diabetes and mental illness is important because it is associated with worse outcomes compared to having diabetes alone. For example, diabetes and depression are associated with an increased risk of functional disability, work loss, microvascular and macrovascular complications, health care costs and mortality compared to those with diabetes alone.(10-15)

The objective of this chapter is to compare the prevalence of diagnosed mental illnesses in people with and without diabetes in Alberta between 1995 and 2005. The mental illnesses evaluated in this chapter include affective disorders (e.g., depression), anxiety disorders, organic (e.g., dementia) and non-organic psychoses (e.g., schizophrenia), and substance abuse disorders.

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CHAPTER �DIABETES AND MENTAL HEALTH DISORDERS IN ALBERTA

METHODS

Data from Alberta Health and Wellness (AHW) Physician Claims databases were utilized for this analysis. This dataset captures Alberta resident demographic information and mental health diagnoses (see Appendix for a listing of all the ICD-9 codes of the mental health conditions reported in this chapter). All adult residents of Alberta aged 20 years or greater were included in these analyses.

From these data, rates of affective disorders, anxiety disorders, non-organic psychoses, organic psychoses and substance abuse disorders for those with and without diabetes were calculated. For people with and without diabetes, the number of people with the mental health diagnoses of interest (numerator) was divided by the number of people in the province or region (denominator), respectively.

Trends over time (1995-2005), as well as regional and age-specific rates for each of the five mental health conditions were calculated. Persons with diabetes were identified as described in the Methods chapter.

As with other rates in the Atlas, direct standardization was used to adjust rates by age and sex for comparisons across time and regions, using the Alberta population according to the 2001 Canadian Census.

FINDINGS

The age and sex-adjusted prevalence of mental illness was consistently higher in people with diabetes compared to people without diabetes. This trend was consistent over the 10 year time period examined (1995–2005) for all of the mental illnesses studied.

The age and sex-adjusted rates of affective disorders were higher in people with diabetes over the 10-year period from 1995 to 2005 (Figure 8.1). Rates for both groups increased until 2002, after which they have decreased. The rates of affective disorders were significantly higher in people with diabetes under the age of 50 compared to people without diabetes of the same age (Figure 8.2), but the rates were relatively equal for those over the age of 50.

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CHAPTER �DIABETES AND MENTAL HEALTH DISORDERS IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ���

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

160

140

120

100

80

60

40

20

0

Year

Rat

e pe

r 10

008-1

Diabetes

No Diabetes

Rat

e pe

r 10

00

160

140

120

100

80

60

40

20

0

8-2

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

160

140

120

100

80

60

40

20

0

Year

Rat

e pe

r 10

008-1

Diabetes

No Diabetes

Rat

e pe

r 10

00

160

140

120

100

80

60

40

20

0

8-2

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Figure 8.1 Age and Sex-Adjusted Rates of Affect�ve D�sorder, ����-�00�

Figure 8.2 Age-Spec�fic Rates of Affect�ve D�sorder, �00�

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CHAPTER �DIABETES AND MENTAL HEALTH DISORDERS IN ALBERTA

Rat

e pe

r 10

00

60

50

40

30

20

10

0

8-3

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Rat

e pe

r 10

00

25

20

15

10

5

0

8-4

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Anxiety disorders have a similar relationship as people with diabetes 50 years of age and under had higher rates compared to people of the same age without diabetes. The rates of anxiety disorders were similar for those over the age of 50 years (Figure 8.3).

Figure 8.3 Age-Spec�fic Rates of Anx�ety D�sorders, �00�

People with diabetes were more than twice as likely to have a diagnosis of non-organic psychoses compared to people without diabetes; this relationship was consistent over the age groups examined, but were more marked in the younger age groups (Figure 8.4). The rate of non-organic psychosis increased in general over the past decade, but more importantly, the rate increased faster in those with diabetes compared to those without (Figure 8.5). In 2005, we observed considerable regional variation of non-organic psychoses in Alberta (Figure 8.6). The health regions of Chinook, Capital, and David Thompson had the highest rates of non-organic psychosis compared to the rest of the province.

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ALBERTA DIABETES ATLAS 2007 ���

Rat

e pe

r 10

00

60

50

40

30

20

10

0

8-3

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Rat

e pe

r 10

0025

20

15

10

5

0

8-4

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Rat

e pe

r 10

00

40

35

30

25

20

15

10

5

0

8-6

Diabetes

No Diabetes

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

18

16

14

12

10

8

6

4

2

0

Year

Rat

e pe

r 10

008-5

Diabetes

No Diabetes

Figure 8.4 Age-Spec�fic Rates of Non-Organ�c Psychoses, �00�

Figure 8.5 Age and Sex-Adjusted Rates of Non-Organ�c Psychoses, ����-�00�

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CHAPTER �DIABETES AND MENTAL HEALTH DISORDERS IN ALBERTA

Rat

e pe

r 10

00

40

35

30

25

20

15

10

5

0

8-6

Diabetes

No Diabetes

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

18

16

14

12

10

8

6

4

2

0

YearR

ate

per

10008-5

Diabetes

No Diabetes

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

7

6

5

4

3

2

1

0

Year

Rat

e pe

r 10

008-7

Diabetes

No Diabetes

Rat

e pe

r 10

00

30

25

20

15

10

5

0

8-8

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Figure 8.6 Age and Sex-Adjusted Rates of Non-Organ�c Psychoses by Reg�on, �00�

From 1995-2005, people with diabetes also had much higher rates of organic psychoses than people without diabetes, with the differences being more pronounced after the year 2000 (Figure 8.7). Age and sex-adjusted rates for both those with and without diabetes increased over the decade of observation. The ratio of the rates for those with and without diabetes was consistent across age groups, however rates for both groups more than tripled in the over 65 population (Figure 8.8).

Figure 8.7 Age and Sex-Adjusted Rates of Organ�c Psychoses, ����-�00�

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CHAPTER �DIABETES AND MENTAL HEALTH DISORDERS IN ALBERTA

ALBERTA DIABETES ATLAS 2007 ���

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

7

6

5

4

3

2

1

0

Year

Rat

e pe

r 10

008-7

Diabetes

No Diabetes

Rat

e pe

r 10

0030

25

20

15

10

5

0

8-8

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Rat

e pe

r 10

00

40

35

30

25

20

15

10

5

0

8-10

Diabetes

No Diabetes

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Rat

e pe

r 10

00

14

12

10

8

6

4

2

0

8-9

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

Figure 8.8 Age-Spec�fic Rates of Organ�c Psychoses, �00�

Substance abuse was more common in people with diabetes, although this relationship was strongest in those under the age of 50 years (Figure 8.9). The Chinook, Northern Lights, and Peace Country health regions had the highest rates of substance abuse disorders (Figure 8.10). This relationship between substance abuse and diabetes has remained relatively consistent over the past decade (Figure 8.11).

Figure 8.9 Age-Spec�fic Rates of Substance Abuse D�sorders, �00�

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CHAPTER �DIABETES AND MENTAL HEALTH DISORDERS IN ALBERTA

Rat

e pe

r 10

00

40

35

30

25

20

15

10

5

0

8-10

Diabetes

No Diabetes

Chinook Palliser Calgary DavidThompson

East Central Capital Aspen PeaceCountry

NorthernLights

Region

Rat

e pe

r 10

00

14

12

10

8

6

4

2

0

8-9

Diabetes

No Diabetes

20-34 35-49 50-64 65-74 75+

Age Group (Years)

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

12

10

8

6

4

2

0

Year

Rat

e pe

r 10

00

8-11

Diabetes

No Diabetes

Figure 8.10 Age and Sex-Adjusted Rates of Substance Abuse D�sorders by Reg�on, �00�

Figure 8.11 Age and Sex-Adjusted Rates of Substance Abuse D�sorders, ����-�00�

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ALBERTA DIABETES ATLAS 2007 ���

DISCUSSION

Consistent with previously published research, prevalence of each of the mental illnesses examined were found to be higher in people with diabetes compared to those without diabetes. This trend has been consistent over the past decade. Given the increased risk of functional disability, complications, healthcare expenditures, and mortality associated with diabetes and comorbid mental illness, these results are quite concerning.

Affective and anxiety disorders were more than 30% higher in people with diabetes, however the excess was limited to people under the age of 50. This result is similar to previously published information from Saskatchewan.(1) As noted earlier, the combination of depression and diabetes is associated with poorer adherence and outcomes and increased health care costs.(13-15)

The prevalence of organic and non-organic psychoses were more than twice as high in people with diabetes. The increased risk of psychoses in diabetes was apparent across all ages. It was particularly interesting that the frequency of non-organic and organic psychosis increased in the last 5 years of the observation period (2001-2005). Potential mechanisms affecting the increased risk of psychoses in diabetes may include the behavioural symptoms of psychosis and the medications used to treat psychosis. Atypical antipsychotic agents used to treat psychosis have been associated with an increased risk of weight gain, type 2 diabetes, hypertension, and dyslipidemia.(9, 16-19) Use of these medications may contribute to the relationship between non-organic and organic psychosis and diabetes and is therefore an area which requires additional research.

It was also of interest that substance abuse disorders were more common in people with diabetes compared to individuals without diabetes. This result may be due to a number of reasons. First, non-organic psychosis, like schizophrenia, is a risk factor for diabetes, and a large number of people with non-organic psychoses also have comorbid substance abuse problems.(20) Second, Aboriginal individuals are at a higher risk of developing diabetes, and also have higher reported substance abuse problems compared to the non-Aboriginal population.(21,22) This relationship is demonstrated by the higher rates of substance abuse in the health regions of Chinook, Northern Lights and Peace Country, which have a large First Nations population (Figure 8.10). Again, the issue of comorbid mental illness and sociodemographic characteristics associated with these comorbid conditions are topics requiring further research.

In summary, people with diabetes are more likely to also have affective disorders, anxiety disorders, organic and non-organic psychoses, and substance abuse disorders compared to their non-diabetic counterparts. Given the increased prevalence of mental illness in people with diabetes, research and health care interventions should focus on strategies to minimize complications and mortality in this population.

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CHAPTER �DIABETES AND MENTAL HEALTH DISORDERS IN ALBERTA

References 1. Brown LC, Majumdar SR, Newman SC, Johnson JA. History of depression increases risk of diabetes in younger adults.

Diabetes Care 2005;28:1063-1067.

2. Arroyo C, Colditz GA, Hu FB, et al. Depressive symptoms and risk of type 2 diabetes in women. Diabetes Care 2004;27:129-133.

3. Everson-Rose SA, Torrens JI, Meyer PM, et al. Depressive symptoms, insulin resistance, and risk of diabetes in women at midlife. Diabetes Care 2004;27:2856-2862.

4. Hill Golden S, Paton Sanford C, Williams JE, et al. Depressive symptoms and the risk of type 2 diabetes. Diabetes Care 2004;27:429-435.

5. Canadian clinical practice guidelines for the prevention and management of diabetes in Canada. Canadian Journal of Diabetes 2003;27(Suppl 2):S1-S152.

6. Dixon L, Weiden P, Delahanty J, et al. Prevalence and correlates of diabetes in national schizophrenia samples. Schizophr Bull 2000;26:903-912.

7. Talbot F, Nouwen A. A review of the relationship between depression and diabetes in adults: is there a link? Diabetes Care 2000;23:1556-1562.

8. Brown ES, Varghese FP, McEwen BS. Association of depression with medical illness: does cortisol play a role? Biol Psychiatry 2004;55:1-9.

9. Lieberman JA, Stroup TS, McEvoy JP, et al, for the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) Investigators. Effectiveness of antipsychotic drugs in patients with chronic schizophrenia. N Engl J Med 2005;353:1209-1223.

10. Egede LE. Effect of depression on work loss and disability bed days in individuals with diabetes. Diabetes Care 2004;27:1751-1753.

11. Black SA, Markides KS, Ray LA. Depression predicts increased incidence of adverse health outcomes in older Mexican Americans with type 2 diabetes. Diabetes Care 2003;26:2822-2828.

12. Finkelstein EA, Bray JW, Chen H, et al. Prevalence and costs of major depression among elderly claimants with diabetes. Diabetes Care 2003;26:415-420.

13. Egede LE, Zheng D, Simpson K. Comorbid depression is associated with increased health care use and expenditures in individuals with diabetes. Diabetes Care 2002;25:464-470.

14. de Groot M, Anderson R, Freedland K, et al. Association of depression and diabetes complications: a meta-analysis. Psychosomatic Medicine 2001;63:619-630.

15. Zhang X, Norris SL, Gregg EW, Cheng YJ, Beckles G, Kahn HS. Depressive symptoms and mortality among persons with and without diabetes. American Journal of Epidemiology 2005;161:652-660.

16. Lindenmayer JP, Czobor P, Volavka J, et al. Changes in glucose and cholesterol levels in patients with schizophrenia treated with typical or atypical antipsychotics. Am J Psychiatry 2003;160:290-296.

17. Lund BC, Perry PJ, Brooks JM, et al. Clozapine use in patients with schizophrenia and the risk of diabetes, hyperlipidemia, and hypertension: a claims-based approach. Arch Gen Psychiatry 2001;58:1172-1176.

18. Meyer JM. A retrospective comparison of weight, lipid, and glucose changes between risperidone- and olanzapine-treated inpatients: metabolic outcomes after 1 year. J Clin Psychiatry 2002;63:425-433.

19. Newcomer JW, Haupt DW, Fucetola R, et al. Abnormalities in glucose regulation during antipsychotic treatment of schizophrenia. Arch Gen Psychiatry 2002;59:337-345.

20. Barry KL, Fleming MF, Greenley J, Widlak P, Kropp S, McKee P. Assessment of alcohol and other drug disorders in the seriously mentally ill. Schizophr Bull 1995;21:313-321.

21. First Nations Regional Longitudinal Health Survey (RHS) 2002/03 - Results for adults, youth and children living in First Nations communities. First Nations Centre, National Aboriginal Health Organization, 2005. Available from: www.naho.ca/firstnations/english/documents/RHS2002-03TechnicalReport_001.pdf

22. Anderson J, McEwan K. Utilization of common analgesic and anxiolytic medications by registered First Nations residents of Western Canada. Subst Use Misuse 2000;35:601–16.

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ALBERTA DIABETES ATLAS 2007 ���

APPENDIX

Alberta Physician Claims Data

D�agnos�s ICD-�-CM Descr�pt�on

Affective.disorders 296.X Affective.psychoses

300.4 Neurotic.depression

301.1 Affective.personality.disorder

309.0 Brief.depressive.reaction

309.1 Prolonged.depressive.reaction

311 Depressive.disorder,.not.elsewhere.classified

Anxiety.disorders 300.X Neurotic.disorders.(exclude.300.4-.Neurotic.depression)

308.X Acute.reaction.to.stress

Non-organic.Psychoses. 295.X Schizophrenia

297.X Paranoid.states.(Delusional.disorders)

298.X Other.non-organic.psychoses

Organic.Psychoses 292.X Drug.psychoses

293.X Transient.organic.psychotic.conditions

294.X Other.organic.psychotic.conditions.(chronic)

Substance.Abuse.disorders 291.X Alcoholic.psychoses

292.X Drug.psychoses

303.X Alcohol.dependence.syndrome

305.2-305.9 Non-dependent.abuse.of.drugs

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ALBERTA DIABETES ATLAS 2007 ���

Brenda R. Hemmelgarn

Ellen L. Toth

Malcolm King

Lynden Crowshoe

Kelli Ralph-Campbell

Chapter � D�abetes and F�rst Nat�ons People �n Alberta

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��� ALBERTA DIABETES ATLAS 2007

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CHAPTER �

DIABETES AND FIRST NATIONS PEOPLE IN ALBERTA

KEY MESSAGES

• The incidence and prevalence of diabetes is more than twice as high among First Nations people, for both males and females, compared to non-First Nations people.

• The increased incidence and prevalence of diabetes for First Nations compared to non-First Nations has remained constant from 1995 to 2005.

• Among First Nations people, the incidence and prevalence of diabetes are higher among females compared to males.

BACKGROUND

The past century has witnessed an epidemiological shift in the diseases affecting Aboriginal populations. Infectious diseases and starvation have given way to chronic disease epidemics like obesity, type 2 diabetes and cardiovascular disease.(1) Limited data is available regarding the burden of diabetes mellitus (DM) among the Aboriginal population although national estimates from the First Nations and Inuit Regional Health Survey showed prevalence rates of diabetes to be 8% and 13% for First Nations men and women, respectively.(2) The more recent 2002/2003 Regional Health Survey report indicates that the prevalence rates have increased to 20%.(3)

The onset of type 2 diabetes among Aboriginal people is also occurring at a much younger age with prevalence rates of 1.1% reported in the 4-19 year old age group in northeastern Manitoba.(4) While a genetic predisposition to type 2 diabetes in Oji-Cree communities in Manitoba and Ontario has been found due to a mutation of the Hepatic Nucleocyte Factor 1 alpha gene,(5) experts agree that the overwhelming reasons for increased prevalence of diabetes and its complications lie with the changes in lifestyle brought about by colonization.(6,7)

The purpose of this report is to compare the incidence and prevalence of diagnosed DM among First Nations and non-First Nations people in Alberta between 1995 and 2005. This report does not include a sub-analyses of the Métis population as they cannot be identified from administrative data sources. Primary data collection in Métis people living on Settlements or in rural communities in Alberta, through the Mobile Diabetes Screening Initiative (MDSi), may permit such estimates in the future.(8)

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METHODS

People with DM were identified using the Alberta Health and Wellness administrative databases by applying the NDSS algorithm (see Methods chapter). First Nations people were identified from the Alberta Health Care Insurance Plan Central Stakeholder Registry file and were defined as any individual residing in Alberta registered under the federal Indian Act and entitled to Treaty status. The Registry file was searched from June 1994 to June 2005 and any individual with a First Nations identifier (First Nations or Inuit) was classified as “First Nations” with all others classified as “non-First Nations”. Aboriginal people in Alberta who were not Registered First Nations, such as First Nations without Treaty status and Métis, were included in the non-First Nations comparison group. First Nations individuals were included whether they were living on or off reserve. In Alberta there are approximately 100,000 First Nations people (62% on reserve)(9) and 70,000 Métis.(10)

For calculation of the prevalence of DM, the proportion of First Nations people who had DM was determined and compared to the proportion of non-First Nations people with DM at the same point in time. This was repeated annually for the years 1995 to 2005.

An incident case of DM was defined as a person who met the NDSS criteria for diabetes with no diabetes claims in the prior two years. Incident rates were calculated for First Nations and non-First Nations people who developed DM in the fiscal years 1995 to 2004.

All rates were age and sex-adjusted to the Alberta population aged 20 and over from the 2001 Canadian Census.

FINDINGS

The age and sex-adjusted prevalence and incidence of DM was approximately twice as high among the First Nations compared to the non-First Nations population (Figure 9.1 and Figure 9.2). These increased rates remained constant over the 10-year period from 1995 to 2005.

The prevalence of DM among First Nations people increased with older ages for both males and females (Figure 9.3 and Figure 9.4). The prevalence was also higher among First Nations females compared to First Nations males however the rate of increase in the prevalence over the 10-year period was more marked for the male population.

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ALBERTA DIABETES ATLAS 2007 ���

First NationsNon-First Nations

First NationsNon-First Nations

14

12

10

8

6

4

2

0

9.1

Rat

e pe

r 10

0

14

12

10

8

6

4

2

0

Rat

e pe

r 10

00

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

9.2

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

First NationsNon-First Nations

First NationsNon-First Nations

14

12

10

8

6

4

2

0

9.1

Rat

e pe

r 10

0

14

12

10

8

6

4

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Rat

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00

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

9.2

Year

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Figure 9.1 Age and Sex-Adjusted Prevalence Rates of D�abetes, F�rst Nat�ons and Non-F�rst Nat�ons People, ����-�00�

Figure 9.2 Age and Sex-Adjusted Inc�dence Rates of D�abetes, F�rst Nat�ons and Non-F�rst Nat�ons People, ����-�00�

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CHAPTER �DIABETES AND FIRST NATIONS PEOPLE IN ALBERTA

First Nations 1995Non-First Nations 1995First Nations 2005Non-First Nations 2005

First Nations 1995Non-First Nations 1995First Nations 2005Non-First Nations 2005

40

35

30

25

20

15

10

5

0

9.3

Rat

e pe

r 10

0

Age Group (Years)20-34 35-49 50-64 65-74 75+

35

30

25

20

15

10

5

0

9.4

Rat

e pe

r 10

0

Age Group (Years)20-34 35-49 50-64 65-74 75+

First Nations 1995Non-First Nations 1995First Nations 2005Non-First Nations 2005

First Nations 1995Non-First Nations 1995First Nations 2005Non-First Nations 2005

40

35

30

25

20

15

10

5

0

9.3

Rat

e pe

r 10

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Age Group (Years)20-34 35-49 50-64 65-74 75+

35

30

25

20

15

10

5

0

9.4

Rat

e pe

r 10

0

Age Group (Years)20-34 35-49 50-64 65-74 75+

Figure 9.3 Age-Spec�fic D�abetes Prevalence Rates of Female F�rst Nat�ons and Non-F�rst Nat�ons People, ���� and �00�

Figure 9.4 Age-Spec�fic D�abetes Prevalence Rates of Male F�rst Nat�ons and Non-F�rst Nat�ons People, ���� and �00�

Similar results are evident with respect to the incidence of DM among the First Nations population (Figure 9.5 and 9.6). The incidence of DM also increased with increasing age, with rates highest for First Nations females aged 50-74.

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First Nations 1995Non-First Nations 1995First Nations 2004Non-First Nations 2004

First Nations 1995Non-First Nations 1995First Nations 2004Non-First Nations 2004

30

25

20

15

10

5

0

9.5

Rat

e pe

r 10

00

Age Group (Years)20-34 35-49 50-64 65-74 75+

25

20

15

10

5

0

9.6

Rat

e pe

r 10

00

Age Group (Years)20-34 35-49 50-64 65-74 75+

First Nations 1995Non-First Nations 1995First Nations 2004Non-First Nations 2004

First Nations 1995Non-First Nations 1995First Nations 2004Non-First Nations 2004

30

25

20

15

10

5

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Age Group (Years)20-34 35-49 50-64 65-74 75+

25

20

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9.6

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00

Age Group (Years)20-34 35-49 50-64 65-74 75+

These age-specific prevalence and incidence rates for First Nations people should be interpreted with caution, especially in the oldest age categories, due to unreliable reporting of deaths and small number of cases. Please refer to the Appendix at the end of this chapter for further data including variability of the point estimates.

Figure 9.5 Age-Spec�fic D�abetes Inc�dence Rates of Female F�rst Nat�ons and Non-F�rst Nat�ons People, ���� and �00�

Figure 9.6 Age-Spec�fic D�abetes Inc�dence Rates of Male F�rst Nat�ons and Non-F�rst Nat�ons People, ���� and �00�

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50

45

40

35

30

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20

15

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9-7

20-34 35-49 50-64 65+

Age Group (Years)

Chinoo

k

David

Thomps

on

Aspen

Pallis

er

East

Centra

l

Peac

e Cou

ntry

Calgar

y

Capita

l

North

ern L

ights

1 Chinook

3 Calgary2 Palliser

4 David Thompson

7 Aspen

8 Peace Country

9 Northern Lights

5 East Central6 Capital

Much higher that provincial average

Higher than provincial average

Average

Lower than provincial average

Much lower than provincial average

Rat

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The age-adjusted DM prevalence across regions for First Nations individuals differs substantially from the regional picture of the entire Alberta population. In 2005, the overall age-adjusted First Nations prevalence rate for DM in Alberta was 11.9%. While the DM prevalence is the highest in the Northern Lights region when reporting on all Albertans (see Chapter 2, Epidemiological Trends), the opposite is true when only including First Nations individuals (Figure 9.7). There is a much lower DM prevalence in First Nations individuals living in the Northern Lights and East Central regions and a much higher DM prevalence among First Nations individuals living in the David Thompson and Chinook regions.

Figure 9.7 Age-Adjusted F�rst Nat�ons D�abetes Prevalence Rates by Reg�on, �00�

To better understand this phenomenon, the age-specific DM prevalence among the First Nations population was calculated by region for 2005 (Figure 9.8). Consistent with the prevalence map in this chapter, age-specific prevalence rates of DM were highest in the Chinook Health Region and lowest in the Northern Lights Health Region.

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50

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40

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30

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Centra

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Capita

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3 Calgary2 Palliser

4 David Thompson

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8 Peace Country

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5 East Central6 Capital

Much higher that provincial average

Higher than provincial average

Average

Lower than provincial average

Much lower than provincial average

Rat

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r 10

0

Figure 9.8 Age-Spec�fic D�abetes Prevalence Rates �n F�rst Nat�ons by Reg�on, �00�

DISCUSSION

The more than two-fold higher incidence and prevalence rates of DM for First Nations compared to non-First Nations people is consistent with national survey data and the small number of studies based on primary data collection in Canada.(4,12-15) These results are also consistent with those reported in Ontario, where the NDSS definition was also applied using administrative data.(16)

It should be noted that the results presented here, based on DM defined from administrative data, are likely an underestimate of the true incidence and prevalence of DM among First Nations people for a variety of reasons. First, a limitation of this definition is the inability to detect undiagnosed diabetes, which is common in First Nations communities. The James Bay Cree (Quebec) and Sandy Lake Oji-Cree (Ontario) communities reported undiagnosed diabetes rates of 2.5% and 10.7% respectively.(1,12) Second, First Nations people who live in rural and remote locations have geographic access to care barriers. As many First Nations people are uncomfortable in the Western cultural medical environments, even when they do receive diagnostic services, they may not return for care. In addition, medical care in remote First Nations communities is provided by nurse practitioners, including care for chronic diseases such as DM. Only claims for diabetes related visits submitted by physicians are included in the administrative data and contribute to the definition of DM used in this Atlas, therefore the estimates of DM provided here are likely underestimated.

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As seen above, differences in delivery of health care explain in part the lower rates of DM seen in First Nations people in the Northern Lights region. However these lower rates in the north are also consistent with findings from the SLICK1 program,(11) and other Northern cultures.(14,15) Although speculative, this may be related to an urban proximity and latitudinal effect on acculturation and lifestyle.

It should also be pointed out that we are unable to report on mortality amongst the First Nations people, due to limitations of the administrative data. Normal management of the Stakeholder Registry includes the removal of deceased persons. During the 1990s, the approach used to identify and remove deceased First Nations people did not fully clear these individuals from the Registry. As a result, the number of deaths is artificially low and the total population is slightly inflated, resulting in biased (i.e., underestimated) mortality rates. While the current process for removing deaths appears to have improved, there are individuals who may have died a decade ago that continue to appear as alive in the databases, making it difficult to accurately estimate mortality in the First Nations population.

Our findings of higher prevalence rates among First Nations women compared to men are also consistent with prior reports. Some of this may be due to increased rates of undiagnosed diabetes in men who are less likely to seek medical care. Of concern, young childbearing aged women show prevalence rates of DM twice as high as non First Nations. In the Sioux Lookout Zone (Ontario) almost three-quarters of First Nations women with gestational diabetes developed type 2 diabetes within four years of their pregnancy, a rate of conversion approximately four times as high compared to other women in general.(16,17) It is quite likely that some Alberta First Nations women captured here had gestational diabetes, which just reinforces the notion of “diabetes begetting diabetes”, consistent with the “hefty fetal phenotype” hypothesis, whereby the intrauterine milieu potentially programs future disease (in this case diabetes).(18)

In summary, consistent with other provinces in Canada, we observed rates of DM incidence and prevalence to be twice as high among First Nations people compared to non-First Nations people, a trend which has remained constant over the past 10 years. While the epidemic of DM among First Nations people requires interventions that target all age groups, these results would suggest that younger age groups, and women in particular, should be the focus of treatment and prevention efforts.

1 Screening for Limbs, I-eyes, Cardiac and Kidneys, a Health Canada sponsored mobile outreach diabetes program in Alberta.

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References 1. Harris SB, Gittelsohn J, Hanley A, Barnie A, Wolever TM, Gao J, et al. The prevalence of NIDDM and associated risk

factors in native Canadians. Diabetes Care 20:185-187, 1997

2. National Steering Committee for the First Nations and Inuit Regional Health Survey: Final report. 1999. Available from: www.hc-sc.gc.ca/fnihb-dgspni/fnihb/aboriginalhealth/reports_summaries/regional_survey.pdf

3. First Nations Regional Longitudinal Health Survey (RHS) 2002/03. Results for adults, youth and children living in First Nations communities. First Nations Centre, National Aboriginal Health Organization, 2005. Available from: www.naho.ca/firstnations/english/documents/RHS2002-03TechnicalReport_001.pdf

4. Dean HJ, Mundy RL, Moffatt M. Non-insulin-dependent diabetes mellitus in Indian children in Manitoba. Canadian Medical Association Journal 147:52-57, 1992

5. Hegele RA, Cao H, Harris SB, Zinman B, Hanley AJ, Anderson CM. Gender, obesity, hepatic nuclear factor-1alpha G319S and the age-of-onset of type 2 diabetes in Canadian Oji-Cree. International Journal of Obesity & Related Metabolic Disorders: Journal of the International Association for the Study of Obesity 24:1062-1064, 2000

6. Young TK, Reading J, Elias B, O’Neil JD. Type 2 diabetes mellitus in Canada’s first nations: status of an epidemic in progress. Canadian Medical Association Journal 163(5):561-566, 2000

7. R.A. Hegele, L.C. Bartlett. Genetics, Environment and Type 2 Diabetes in the Oji-Cree Population of Northern Ontario. Canadian Journal of Diabetes 27(3):256-261, 2003.

8. Toth E, Cardinal K, Moyah D, Ralph-Campbell K. Partnerships to Address the Diabetes Epidemic in Aboriginal Communities in Alberta. Canadian Journal of Diabetes 29(4):415-419, 2005.

9. Historical Trends – Registered Indian Population Alberta Region 1982-2005. First Nations and Northern Statistics Section, data from Indian Registry, 1982-2005 as at December 31st – Indian and Northern Affairs Canada, 2006. Available from: www.ainc-inac.gc.ca/pr/sts/htrip/ht-ab_e.pdf

10. 2001 census – Analysis groups – Métis. Statistics Canada – Ministry of Industry, 2003. Available from: www12.statcan.ca/english/census01/products/analytic/companion/abor/pdf/96F0030XIE2001007.pdf

11. Virani S, Datta NK. The SLICK Project: Screening for Limb, I-Eye, Cardiovascular, and Kidney Complications of Diabetes Using Mobile Diabetes Clinics. An Alberta First Nations Project. 2004. Available from: www.hc-sc.gc.ca/hcs-sss/pubs/chipp-ppics/2004-slick/slick_appendix_e.html

12. Dannenbaum D, Verronneau M, Torrie J. Comprehensive computerized diabetes registry - Serving the Cree of Eeyou Istchee (eastern James Bay). Canadian Family Physician 45:364-370, 1999

13. Shar BR, Anand S, Zinman B, Duong-Hua M. Diabetes and First Nations People: In Hux JE, Booth GL, Slaughter PM, Laupacis A (eds). Diabetes in Ontario: An ICES Practice Atlas: Institute for Clinical Evaluative Sciences. 2003:13.231l-13.248.

14. Pollex RL, Khan HM, Connelly PW, Young TK, Hegele RA. The metabolic syndrome in Inuit. Diabetes Care 27:1517-1518, 2004

15. Young TK. Contributions to chronic disease prevention and control: studies among the Kivalliq Inuit since 1990. International Journal of Circumpolar Health 62:323-330, 2003

16. Mohamed N, Dooley J. Gestational diabetes and subsequent development of NIDDM in aboriginal women of northwestern Ontario. International Journal of Circumpolar Health 57 Suppl 1:355-358, 1998

17. Ben-Haroush A, Yogev Y, Hod M. Epidemiology of gestational diabetes mellitus and its association with type 2 diabetes. Diabetic Medicine 21:103–113, 2003

18. Godfrey KM, Barker DJ. Fetal programming and adult health. Public Health Nutrition 4:611-624, 2001

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APPENDIX

Prevalence Rates of Diabetes in First Nations and Non-First Nations, 1995 and 2005

First Nations - Rates (per 100)

���� �00�Women Rate Lower CI Upper CI Rate Lower CI Upper CI

20-34 1.97 1.73 2.23 2.30 2.06 2.5635-49 7.46 6.83 8.08 8.04 7.55 8.5350-64 20.93 19.26 22.71 23.87 22.59 25.1665-74 34.03 29.61 38.91 35.04 31.97 38.3275+ 21.51 16.89 27.01 36.18 31.28 41.63Men Rate Lower CI Upper CI Rate Lower CI Upper CI

20-34 0.57 0.44 0.73 1.18 1.01 1.3735-49 5.44 4.89 6.03 5.54 5.13 5.9550-64 15.58 14.15 17.12 19.42 18.21 20.6365-74 19.19 15.83 23.06 28.91 26.12 31.9275+ 13.99 10.04 18.98 22.09 17.87 27.01

Overall

Age/Sex.Adjusted 9.90 9.47 10.34 11.93 11.57 12.28

Non-First Nations - Rates (per 100)

���� �00�Women Rate Lower CI Upper CI Rate Lower CI Upper CI

20-34 1.38 1.34 1.42 0.98 0.95 1.0235-49 2.29 2.24 2.34 3.41 3.35 3.4750-64 4.81 4.70 4.92 7.11 7.01 7.2165-74 9.25 9.04 9.46 12.91 12.67 13.1475+ 10.43 10.18 10.67 14.54 14.29 14.78Men Rate Lower CI Upper CI Rate Lower CI Upper CI

20-34 0.57 0.55 0.60 0.71 0.68 0.7435-49 1.71 1.66 1.75 2.68 2.62 2.7350-64 6.53 6.40 6.65 9.12 9.01 9.2465-74 11.46 11.22 11.71 17.26 16.99 17.5475+ 13.23 12.89 13.58 18.58 18.24 18.92

Overall

Age/Sex.Adjusted 3.68 3.65 3.71 5.17 5.14 5.20

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Incidence Rates of Diabetes in First Nations and Non-First Nations, 1995 and 2004

First Nations - Rates (per 1000)

���� �00�Women Rate Lower CI Upper CI Rate Lower CI Upper CI

20-34 2.25 1.49 3.28 3.28 2.42 4.3435-49 5.50 3.87 7.58 7.00 5.55 8.7150-64 14.84 10.21 20.84 20.73 16.56 25.6465-74 28.24 14.59 49.32 22.60 13.8 34.9075+ 14.60 3.98 37.38 20.65 8.30 42.54Men Rate Lower CI Upper CI Rate Lower CI Upper CI

20-34 0.61 0.25 1.26 2.67 1.89 3.6735-49 6.76 4.90 9.11 9.55 7.85 11.5050-64 15.04 10.54 20.83 16.57 12.82 21.0865-74 4.15 0.50 14.99 19.67 11.84 30.7275+ 7.87 0.95 28.44 21.41 8.61 44.11

Overall

Age/Sex.Adjusted 8.10 6.82 9.55 10.84 9.68 12.09

Non-First Nations - Rates (per 1000)

���� �00�Women Rate Lower CI Upper CI Rate Lower CI Upper CI

20-34 1.47 1.34 1.61 1.42 1.29 1.5535-49 1.92 1.76 2.07 2.94 2.76 3.1150-64 5.17 4.81 5.53 8.18 7.81 8.5565-74 7.30 6.69 7.91 12.25 11.50 13.0175+ 6.40 5.77 7.07 11.12 10.38 11.86Men Rate Lower CI Upper CI Rate Lower CI Upper CI

20-34 0.46 0.38 0.54 0.85 0.75 0.9635-49 2.16 2.00 2.32 3.87 3.67 4.0750-64 7.50 7.07 7.93 10.86 10.43 11.2865-74 11.11 10.3 11.91 16.02 15.11 16.9375+ 9.73 8.75 10.79 14.89 13.82 15.97

Overall

Age/Sex.Adjusted 3.50 3.41 3.60 5.38 5.28 5.48

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Chapter �0 Key F�nd�ngs and Pol�cy Opt�ons

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CHAPTER �0

KEY FINDINGS AND POLICY OPTIONS

SUMMARY

The Alberta Diabetes Atlas data presents a clear picture of the burden that diabetes continues to place on Albertans, with over 1,000 new cases identified each month. Over 5%, or 1 in 20 adults in Alberta are living with diabetes. An aging population will further drive the increasing prevalence over the coming years. While it appears that rates of some complications and comorbidities are stabilizing or even decreasing for people with diabetes in Alberta, the real burden is the actual number of people with these conditions. In most cases, the actual number of people with diabetes who developed complications or comorbidities has increased over the past decade, signaling the increasing demand for health care resources for diabetes and related conditions over the next decade.

All of the findings in this Alberta Diabetes Atlas offer substantial evidence for the need to enhance primary and secondary prevention efforts in order to stem the tidal wave we are beginning to experience with respect to complications and comorbidities as a result of diabetes. This will require substantial investment now to reduce the health care burden and improve the health of Albertans for decades to come.

In this chapter we have attempted to make this Alberta Diabetes Atlas more useful to you, the reader. We identified what we feel are several important Key Findings in interpreting the evidence presented in the Atlas, and linked these with potential Policy Options to consider in managing these observed patterns. We do not see these as the only options, or the final word on what must be done, but rather the beginning of a dialogue amongst stakeholders on how to best deal with the serious and growing problem of diabetes and related conditions in Alberta. As a reader, you are an important stakeholder, and we encourage you to engage in discussion with other stakeholders including patients and the public, health care professionals, managers, policy-makers and researchers. We encourage this dialogue as we continue to enhance the Alberta Diabetes Surveillance System (ADSS), to include more information on patterns of health care delivery and health outcomes for people with diabetes, and to improve our ability to interpret and disseminate our findings.

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KEY FINDINGS

1. The prevalence and incidence of diabetes are increasing in Alberta, and especially among older adults.

Policy Options

• Enhance investment in diabetes prevention efforts across all ages.

• Institute an intensive public education program aimed at lifestyle modification to decrease the risk factors for developing diabetes, most importantly obesity and physical inactivity.

2. People with diabetes have a markedly increased chance of having a heart attack or stroke, requiring dialysis, going blind, or having a lower limb amputation, compared to people without diabetes. Some success has been achieved in reducing heart disease and strokes in recent years. The chance of developing these complications can be further reduced with more aggressive control of risk factors, such as blood pressure, cholesterol and blood sugar. Still, reports from Alberta and other provinces suggest sub-optimal use of evidence-based therapies to reduce these risks.

Policy Options

• Actively disseminate evidence-based guidelines about optimal medication use in people with diabetes, especially to General Practitioners.

• Establish risk factor modification clinics throughout the province, aimed at people with diabetes. These clinics could be coordinated by appropriately trained teams of allied health professionals including nurses, pharmacists and dieticians.

• Regularly monitor the trends in the number and rates of complications over time, and use this information to plan services for the future.

• Consider financial barriers to individuals for the use of evidence-based medications aimed at improving risk, given that people with diabetes are often on many of these medications at the same time.

3. The majority of medical care for people with diabetes is from General Practitioners. Still, people with diabetes see medical specialists three times more often than people without diabetes.

Policy Options

• Enhance investments in strategies to improve quality of care by primary health care providers.

• Ensure that there are sufficient primary care providers in Alberta. Consider access to allied health professional primary care providers in rural and non-metro health regions.

• Regularly monitor the trends of the number and type of complications of diabetes, and use this information to plan for access to specialized services in the future, such as dialysis and specialized cardiac procedures.

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4. Mental illness, including depression and psychoses, is much more common in people with diabetes, and has been increasing in prevalence over the past decade.

Policy Options

• Enhance screening for complications in both populations – screening for diabetes in people with mental illness and for mental illness in people with diabetes.

• Research and health care interventions should focus on strategies to minimize complications and mortality in this population.

5. People with diabetes living in northern and non-metro health regions have lower rates of specialists care visits and higher use of hospital and emergency departments for acute and chronic complications of diabetes.

Policy Options

• Ensure an adequate supply of primary care providers and access to all diabetes services in all regions of Alberta. Consider access to allied health professional primary care providers in rural and non-metro health regions such as nurses, pharmacists and dieticians.

• Regularly monitor the trends in the number and type of complications of diabetes, and use this information to plan for access to specialized services in the future, such as dialysis and specialized cardiac procedures.

6. Screening for diabetic eye disease is an important strategy in preventing blindness; despite this strong evidence, the frequency of eye examinations by experienced professionals is lower than suggested by practice guidelines.

Policy Options

• Increase awareness of the need for regular eye examinations by actively disseminating the guidelines to both patients and providers.

• Enhance surveillance to include care provided by all eye care professionals.

• Consider increased use of teleophthalmology to enhance access for required eye examinations in northern and non-metro health regions.

7. The prevalence of diabetes is twice as high in the First Nations population compared to the rest of the population in Alberta.

Policy Options

• Target culturally appropriate preventive and therapeutic interventions to First Nations people and communities, ensuring access to a full range of necessary services.

• Work with First Nations peoples and communities to better understand the impact of diabetes and related conditions, and enhance ongoing surveillance programs in Aboriginal populations.

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8. While the ADSS provides important new information about diabetes and related conditions, there are several limitations in our full understanding of the care and outcomes for people with diabetes in Alberta.

Policy Options

• Surveillance should be expanded to include information about risk factors, such as smoking, obesity, physical inactivity, high blood pressure and high cholesterol, and should be linked with information on use of health services and long-term outcomes.

• Surveillance should be expanded to include other special populations (e.g., diabetes in pregnancy, diabetes in children) and other comorbid conditions (e.g., foot disease, cancer).

• The number and location of diabetes clinics and information about workload and outcomes associated with these clinics needs to be collected and shared on a regular basis.

• Reliable information on mortality amongst the First Nations population is lacking at present and should be made available through the administrative databases.

RESEARCH IMPLICATIONS

Surveillance activities such as the Alberta Diabetes Surveillance System provide a general overview of the burden of diabetes and its associated health conditions, with a population-based perspective. After seeing the general picture from a bird’s eye view, there are many questions generated about what underlies these observed trends. Clinical and health policy research questions are often stimulated by health surveillance activities, such as the information presented in this Alberta Diabetes Atlas. Discussions among ADSS contributors have raised a number of important questions which should be addressed through more in-depth investigation:

• Are there differences in health care utilization by socioeconomic status throughout Alberta (across and within health regions)?

• Have recently established diabetic nephropathy prevention programs lead to reductions in rates of end-stage renal disease in Alberta?

• Do regions with higher rates of eye examinations or eye disease procedures have lower rates of blindness?

• Is there a better way to define mental illnesses using the administrative databases?

• How many Albertans will be living with diabetes in the next 10 years?

These questions, and many others, can be addressed with data from the same administrative databases as used in the ADSS, and possibly linked with other valuable data sources in Alberta. Answers to these questions can help to improve the quality of care for people with diabetes and the efficiency of health care delivery in Alberta. Information from the ADSS is intended to spur such research activities to achieve these goals.

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Aboriginalan.inclusive.term.which.refers.to.all.Canadian.aboriginal.peoples.regardless.of.residential.location.as.compared.to.First.Nations,.which.refers.to.“status.Indians”..Collectively,.First.Nations,.Inuit,.and.Métis.peoples.are.known.as.Aboriginal.peoples,.First.peoples,.or.Indigenous.peoples,.bands,.or.nations.

ACE inhibitorsangiotensin.converting.enzyme.inhibitors.

Accessin.the.context.of.this.publication,.the.ability.to.receive.health.care.services.without.barriers.

Acutean.effect.on.health.that.happens.rapidly;.in.the.context.of.acute.diabetic.complications,.consequences.of.diabetes.that.occur.over.a.short.period.of.time.and.are.fully.reversible.

Acute care hospitalan.institution.that.provides.in-hospital.medical.or.surgical.treatment

Acute myocardial infarction (AMI)also.called.a.heart.attack..This.occurs.when.a.blood.clot.completely.blocks.one.of.the.arteries.that.provide.oxygen-rich.blood.to.the.heart.muscle.

Adjusted ratea.rate.that.controls.for.a.particular.set.of.characteristics.within.a.study.population.that.may.be.related.to.the.outcome.of.interest.(e.g.,.age.and.sex);.allows.for.comparisons.across.areas.or.institutions.with.different.population.characteristics.

Administrative Datainformation.that.is.primarily.collected.for.record.keeping,.finances.or.purposes.other.than.research.

Aggregated dataa.dataset.wherein.individual.records.are.combined,.usually.by.age.and/or.sex..Once.data.are.aggregated,.it.is.not.possible.to.identify.the.results.for.an.individual.person.

Alberta Physician Claims Dataa.dataset.that.contains.information.from.when.physicians.submit.claims.for.reimbursement.for.services.provided..Three.diagnostic.codes.are.included.in.addition.to.other.information.

Ambulatory caremedical.care,.provided.in.a.clinic.or.office,.where.the.patient.is.not.admitted.to.hospital.

Ambulatory Care Classification System (ACCS)Facility-based.ambulatory.care.information.developed.in.1998..Contains.data.for.same-day.surgery,.day.procedures,.diagnoses.and.emergency.department.visits..This.database.was.used.when.reporting.emergency.department.encounters.for.different.conditions.in.this.Atlas..

Anginaa.type.of.chest.pain.that.occurs.when.there.is.not.enough.blood.flow.to.the.heart.muscle..This.is.usually.the.result.of.a.narrowing.of.the.arteries.that.supply.blood.to.the.heart.

Angiography (see coronary angiography)the.X-ray.visualization.of.the.internal.anatomy.of.the.heart.and.blood.vessels.after.a.dye.is.injected.into.the.coronary.arteries.

Atherosclerosisthe.build-up.of.fat,.calcium.and.other.substances.under.the.inner.lining.of.an.artery..Atherosclerosis.may.cause.the.arteries.to.the.heart.to.become.narrower,.leading.to.angina.or.a.heart.attack.

Beta-blockers (or beta-adrenergic receptor blocking agents)a.class.of.drugs.used.for.the.treatment.of.hypertension,.heart.attacks,.angina.and.heart.failure;.reduces.stress.on.the.heart.by.slowing.down.the.heart.rate,.thus.reducing.the.oxygen.requirement.

Biassystematic.deviation.from.the.truth.

Body mass index (BMI)a.method.of.assessing.body.weight.while.taking.height.into.account;.calculated.by.dividing.weight.by.height.squared.(wt.[kg]./.ht.[meters]2)..A.BMI.score.between.20.and.25.is.considered.healthiest.on.average;.over.27.is.considered.overweight;.30.is.the.threshold.for.obesity.

Burden of Illnessthe.short-.and.long-term.physical,.emotional,.social,.financial,.familial.and.societal.effects.associated.with.a.particular.illness.or.condition;.provides.an.estimation.of.the.overall.scope.and.impact.of.a.particular.disease.

GLOSSARY

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GLOSSARY

Canadian Classification of Procedures (CCP)a.coding.system.used.in.many.administrative.databases.for.classifying.surgical.and.medical.procedures;.developed.by.Statistics.Canada.in.1987.

Canadian Institute for Health Information (CIHI)a.federally.chartered.but.independent,.non-profit.organization.that.collects.and.processes.health.data.from.a.number.of.sources,.particularly.from.hospitals..All.Canadian.hospitals.are.required.to.submit.demographic.and.clinical.information.about.all.hospital.admissions.and.discharges..CIHI.assembles.these.data.into.a.Discharge.Abstract.Database.(DAD),.which.is.the.data.source.for.many.analyses.

Canadian Organ Replacement Registry (CORR)a.database.that.contains.information.on.the.use.and.outcomes.of.vital.organ.transplantation.and.renal.dialysis.activities.in.Canada.

Cataract Opacity.of.the.lens.or.capsule.of.the.eye,.causing.impairment.of.vision.or.blindness.

Comorbid conditions or illnesses (also called comorbidity)a.set.of.medical.conditions.present.in.an.individual,.other.than.the.condition.of.primary.interest.

Confidence intervalan.indication.of.the.precision.of.a.population.value;.wider.intervals.indicate.lesser.precision.while.narrower.intervals.indicate.greater.precision.

Coronary angiographythe.X-ray.visualization.of.the.internal.anatomy.of.the.heart.and.blood.vessels.after.a.dye.is.injected.into.the.coronary.arteries.

Coronary artery bypass graft (CABG) surgeryan.open-heart.surgical.procedure.that.helps.to.improve.blood.circulation.for.patients.with.blockages.of.the.coronary.arteries.of.the.heart.

Coronary artery disease (CAD) (also ischemic heart disease)atherosclerosis.involving.the.arteries.to.the.heart..This.causes.narrowing.of.the.arteries.leading.to.angina.or.a.heart.attack.

Coronary revascularizationa.procedure.that.aims.to.restore.the.blood.flow.through.the.arteries.to.the.heart.with.either.CABG.or.coronary.angioplasty.

Cross-sectional analysesanalyses.that.examine.the.presence.of.diseases.and.other.variables.of.interest.as.they.exist.in.a.defined.population.at.a.single.point.in.time.

Crude mortality ratea.mortality.rate.that.is.not.adjusted.

Diabetes mellitusa.disease.characterized.by.an.elevation.in.blood.sugar.that.can.lead.to.many.long-term.complications..DM.is.diagnosed.by.the.presence.of.one.of.the.following:.(1).fasting.plasma.glucose.>7.mmol/L;.(2).symptoms.of.DM.(increased.thirst.and/or.urination,.fatigue,.unexplained.weight.loss).plus.a.casual.(non-fasting).plasma.glucose.>11.1.mmol/L;.or.(3).plasma.glucose.in.the.2-hour.sample.of.an.oral.glucose.tolerance.test.(OGTT).>11.1.mmol/L.

Diabetic ketoacidosis (DKA)an.acute.and.potentially.life-threatening.complication.of.DM.resulting.in.elevated.blood.sugar.levels,.dehydration,.ketone.production,.and.other.metabolic.abnormalities;.can.be.the.first.sign.of.DM,.or.may.be.triggered.by.another.illness.or.poor.adherence.with.DM.medications.in.persons.with.pre-existing.type.1.DM,.or.occasionally.in.the.setting.of.type.2.DM.

Diabetic retinopathy (DR)retinal.changes.in.persons.with.diabetes.marked.by.hemorrhages.or.microaneurysms.or.sharply-defined.waxy.deposits.which.can.impair.vision.or.cause.blindness.(most.patients.with.mild.DR.do.not.suffer.loss.of.vision).

Dialysis (also renal or kidney dialysis)a.life-saving.treatment.that.individuals.with.end.stage.renal/kidney.disease.(see.below).need.on.a.regular.basis.in.order.to.clean.toxins.out.of.the.blood..Two.forms.of.dialysis.can.be.used:.hemodialysis,.which.requires.using.a.dialysis.machine.to.clean.the.blood.directly.(usually.every.2.to.3.days),.and.peritoneal.dialysis.which.involves.exchanging.fluid.into.and.out.of.the.abdomen.(usually.several.times.per.day).

Direct Standardization (see also adjusted rate)a.statistical.method.whereby.the.specific.rates.in.a.study.population.are.adjusted.for.differences.in.population.composition;.the.rate.represents.what.the.crude.rate.would.have.been.in.the.study.population.if.the.population.had.the.same.distribution.as.the.standard.population.(with.respect.to.the.variables.for.which.the.standardization.is.carried.out).

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Discharge Abstract Database (Inpatient hospital data)Administrative.data.from.hospitals..Hospitals.prepare.a.discharge.summary.containing.information.retrieved.from.patient.charts.(for.those.patients.assigned.to.an.inpatient.bed)..These.data.contain.clinical.information.(diagnoses.and.procedures),.which.is.sent.by.all.provinces.to.CIHI.

End Stage Renal Disease (ESRD)a.condition.in.which.the.kidneys.are.functioning.at.a.very.low.level..The.kidneys.are.no.longer.able.to.remove.toxins.from.the.blood.and.dialysis.or.transplantation.is.required.

Epidemiologythe.study.of.the.distribution.and.determinants.of.health.related.states.or.events.in.specified.populations,.and.the.application.of.this.study.to.prevent.or.treat.health.problems.

Fee-for-servicethe.reimbursement.scheme.by.which.the.Alberta.Health.and.Wellness.pays.physicians.for.services.provided..The.claims.that.physicians.submit.for.payment.under.this.plan.are.documented.in.a.database,.and.can.be.used.to.track.service.provision.

First Nations is.a.term.of.ethnicity.used.in.Canada..It.refers.to.Indigenous.of.North.America.located.in.what.is.now.Canada,.and.their.descendants,.who.are.not.Inuit.or.Métis.

Gestational Diabetes (GD)diabetes.that.develops.during.pregnancy.and.resolves.after.the.baby.is.born.

Glaucomais.caused.by.impaired.absorption.of.the.aqueous.humour.(gel-like.liquid.in.the.eye.itself).causing.increased.intraocular.pressure.(pressure.within.the.eye).which.produces.gradual.vision.loss.with.reduced.nighttime.vision.

Glycated (glycosylated) hemoglobin (A1c)a.laboratory.test.that.reflects.the.average.glucose.level.over.a.two.to.three.month.period.

Glycemic controlthe.level.of.blood.sugar.control.obtained..Recommended.targets.in.the.2003.CDA.Guidelines.include.a.fasting.blood.sugar.of.4.0–7.0.mmol/L,.a.blood.sugar.1–2.hours.after.meals.of.5.0–11.0.mmol/L,.and.a.glycated.hemoglobin.(A1C).that.is.<.7%.in.order.

to.reduce.the.risk.of.microvascular.and.macrovascular.complications.

Health promotiondefined.by.the.World.Health.Organization.as.a.“process.of.enabling.people.to.increase.control.over,.and.improve,.their.health”.

Health-related quality of life (HRQL)measures.various.components.of.well-being.including.physical,.mental,.emotional,.and.social.functioning.

Heart Failure (HF)a.condition.where.the.heart.fails.to.pump.vigorously.enough.to.meet.the.needs.of.the.body;.may.cause.fluid.to.back.up.into.the.lungs.

Hemodialysistreatment.done.when.a.patient’s.own.kidneys.no.longer.function;.the.patient’s.blood.is.circulated.outside.the.body.along.an.artificial.membrane.within.a.dialysis.machine.which.cleans.the.blood.of.toxins.and.removes.excess.fluid.

Hyperglycemiaabnormally.high.blood.sugar.level.

Hyperglycemic emergenciesdiabetic.ketoacidosis.or.hyperosmolar.nonketotic.coma.

Hyperlipidemiaa.general.term.for.high.concentrations.of.lipids.or.fat.substances.(e.g.,.cholesterol).in.the.blood.

Hyperosmolar nonketotic coma (HNKS)an.acute.and.potentially.life-threatening.complication.of.DM.resulting.in.severely.elevated.blood.sugar.levels,.dehydration,.and.other.metabolic.abnormalities;.can.be.the.first.sign.of.DM,.or.may.be.triggered.by.another.illness.or.poor.adherence.with.DM.medications.in.persons.with.pre-existing.type.2.DM.

Hypertensionelevated.blood.pressure.

Hypoglycemialow.blood.sugar.levels;.patients.who.use.insulin.or.antihyperglycemic.medications.are.at.an.increased.risk.for.developing.hypoglycemia,.as.a.side-effect.of.the.medications.

Impaired fasting glucose (IFG)is.a.condition.in.which.fasting.blood.glucose.levels.are.above.normal.(between.6.1.and.6.9.mmol/L.according.to.the.2003.CDA.guidelines),.but.not.yet.within.the.diabetic.range.(>7.0.mmol/L).

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Impaired glucose tolerance (IGT)a.condition.in.which.blood.glucose.levels.two.hours.after.an.oral.glucose.tolerance.test.are.above.normal.(between.7.8.and.11.0.mmol/L),.but.not.yet.within.the.diabetic.range.(≥11.1mmol/L)..Up.to.five.percent.of.people.with.IGT.develop.diabetes.each.year.

Incidencea.rate.that.describes.the.frequency.of.new.cases.of.a.given.condition.over.a.specific.time.period.(usually.one.year).

Incident casesnew.cases.of.a.given.condition,.in.a.specified.population.

International Classification of Diseases (diagnostic codes)derived.from.ICD-9-CM.and.ICD-10-CA,.a.set.of.internationally.accepted.codes.for.classification.of.medical.diagnoses,.conditions.and.procedures;.medical.records.staff.use.these.codes.when.transcribing.from.medical.charts.to.the.hospital.database.that.is.submitted.to.CIHI.

Ischemic heart disease (IHD) (see coronary artery disease)atherosclerosis.involving.the.arteries.to.the.heart..This.causes.narrowing.of.the.arteries.leading.to.angina.or.a.heart.attack.

Length of stay (LOS) the.number.of.days.spent.in.hospital.for.a.particular.procedure.or.illness.

Lipid-lowering medicationsclasses.of.drugs.used.to.treat.hyperlipidemia,.including.HMG.CoA.reductase.inhibitors.(also.known.as.statins),.binding.resins.and.fibrates.

Lower limb amputationsurgical.amputation.of.the.leg,.foot.or.toe.

Macrovascular diseasedamage.to.large.blood.vessels.associated.with.diabetes.Macrovascular.disease.includes.coronary.heart.disease(CHD),.stroke.and.peripheral.vascular.disease.(PVD).

Major amputationsamputation.performed.between.the.ankle.and.the.thigh.

Meanthe.sum.of.the.values.in.a.sample.divided.by.the.number.of.values;.also.known.as.the.average.

Medianthe.middle.observation.or.the.one.that.divides.a.distribution.into.two.equal.halves;.also.known.as.the.50th.percentile.

Microvascular diseasedamage.to.small.blood.vessels.associated.with.diabetes..Microvascular.disease.affects.the.kidneys,.peripheral.nerves.and.eyes.in.people.with.diabetes.

Minor amputationsamputations.at.the.level.of.the.foot.or.below.

Morbidityan.overall.term.to.describe.non-fatal.consequences.of.an.illness;.often.refers.to.the.extent.of.hospitalization,.symptom.burden.or.disability.within.a.population.

Mortality ratethe.number.of.deaths.in.a.given.population.divided.by.the.number.of.people.alive.within.that.population;.may.be.adjusted.for.age,.sex.or.other.sets.of.risk.factors.

Most responsible diagnosisfor.a.given.hospitalization,.the.condition.that.accounts.for.the.majority.of.the.days.spent.in.hospital;.used.for.administrative.purposes.

National Diabetes Surveillance System (NDSS)an.initiative.involving.provinces,.territories.and.Aboriginal.groups.in.diabetes.surveillance.by.using.administrative.data.to.conduct.analyses.using.common.definitions;.allows.the.data.to.be.meaningfully.aggregated.to.provide.a.national.profile.of.diabetes.

Nephropathyany.disease.of.the.kidney.

Outcomethe.factor.that.is.being.studied.such.as.death.or.hospitalization.

Outpatient carehealth.care.delivered.to.patients.outside.the.context.of.hospital.admission;.in.outpatient.clinics,.walk-in.clinics.and.ambulatory.clinics.

Percutaneous coronary intervention (PCI) (also called coronary angioplasty or angioplasty)a.catheter-based.procedure.in.which.a.thin.tube.(catheter).is.inserted.through.an.artery.in.the.arm.or.groin.and.threaded.up.through.the.artery.to.the.heart..Diagnostic.and.treatment.procedures.can.be.performed.through.the.catheter.using.special.instruments.to.restore.normal.blood.flow.

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Peripheral arterial disease (PAD)narrowing.of.the.arteries.in.the.feet,.legs,.abdomen,.pelvis,.arms,.or.neck..PAD.can.result.in.a.broad.spectrum.of.functional.impairment,.from.a.decrease.in.pain-free.walking.distance.to.amputation..In.this.atlas,.we.report.on.PAD.affecting.the.lower.extremities.

Peritoneal dialysisa.type.of.treatment.used.when.a.person’s.kidneys.fail;.the.removal.of.fluid.and.toxins.by.exchanging.fluid.into.and.out.of.the.abdomen,.using.the.body’s.own.peritoneal.membrane.

Pharmacotherapythe.treatment.of.disease.using.drugs.

Pre-DiabetesImpaired.fasting.glucose.(IFG).or.impaired.glucose.tolerance.(IGT).are.commonly.referred.to.as.pre-diabetes.

Prevalencethe.proportion.of.people.in.a.population.who.have.a.particular.condition.at.a.given.point.or.period.in.time.

Prevalent casesall.persons.with.the.condition.of.interest.at.a.point.in.time.(contrasts.with.incident.cases.which.includes.only.those.newly-diagnosed).

Primary carehealth.care.that.is.delivered.by.family.or.general.“front.line”.practitioners.

Proliferative retinopathya.severe.form.of.diabetic.retinopathy.characterized.by.the.growth.of.abnormal.new.blood.vessels.on.the.retina,.extending.into.the.vitreous.humour;.may.lead.to.loss.of.vision.

Rate ratiothe.ratio.of.two.rates..In.epidemiologic.terms,.it.is.the.comparison.of.the.rate.in.the.population.with.the.disease.of.interest.to.the.rate.in.the.population.without.the.disease.of.interest.

Retinal (eye) examinations microvascular.disease.in.DM.can.be.directly.visualized.at.the.back.of.the.eye.on.clinical.examination;.screening.for.diabetic.retinopathy.should.involve.a.dilated.examination.of.the.retina.by.an.experienced.health.professional..In.this.Atlas,.we.report.on.eye.examinations.by.ophthalmologists.

Retinal laser treatment (retinal photocoagulation)is.performed.using.laser.technology;.early.treatment.with.this.technique.decreases.the.risk.of.severe.vision.loss.from.proliferative.diabetic.retinopathy.and.macular.edema;.the.effectiveness.of.treatment.is.best.before.vision.loss.occurs.and.falls.sharply.if.applied.later.

Retinopathynon-inflammatory.degenerative.disease.of.the.retina.

Revascularizationa.procedure.that.aims.to.restore.the.blood.flow.through.the.arteries.by.making.the.diameter.of.the.arteries.larger.or.by.bypassing.the.affected.area.

Risk factora.characteristic.that.is.more.prevalent.among.the.people.who.have.a.particular.disease.or.outcome.than.those.who.do.not.

Screeningan.initial.examination.in.which.identification.of.unrecognized.disease(s).or.conditions.are.attempted.by.using.tests,.procedures.or.examinations.(for.example,.taking.blood.pressure.to.determine.if.an.individual.has.hypertension).

Sensitivitythe.probability.that.a.diagnostic.test.is.positive.in.patients.who.have.the.disease/condition;.a.measure.of.a.test’s.capacity.to.detect.all.cases.

Skin and soft tissue infectionsincludes.foot.ulcers.and.other.localized.infections.

Socioeconomic statusa.label.that.describes.a.combination.of.social.and.economic.factors,.such.as.education.and.income.

Specific raterate.of.an.event.in.a.specific.sub-population.(e.g.,.sex-specific.AMI.rates.will.provide.rates.of.AMI.in.men.and.women.separately).

Specificitythe.probability.that.a.diagnostic.test.is.negative.in.patients.who.do.not.have.the.disease/condition;.a.test.with.low.false-positive.rate.is.specific.

Statinssynthetically-derived.cholesterol-lowering.agents.

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Strokethe.sudden.development.of.focal.neurological.deficits.usually.related.to.impaired.cerebral.blood.flow;.also.called.a.cerebrovascular.accident.(CVA)..Strokes.can.be.either.hemorrhagic.(caused.by.bleeding.into.the.brain).or.ischemic.(caused.by.blockages.in.the.blood.vessels.to.the.brain).

Transient ischemic attack (TIA)is.a.mini-stroke.caused.by.a.temporarily-blocked.blood.vessel.which.leaves.no.permanent.brain.damage.

Unstable Angina (UA)a.change.in.the.usual.pattern.of.angina..Blood.flow.to.the.heart.has.become.more.inadequate,.either.because.the.main.artery.to.the.heart.has.become.narrower,.or.because.the.demand.for.oxygen.to.the.heart.has.increased,.leading.to.more.severe.or.frequent.symptoms.

Vital Statisticsa.registry.of.Canadian.births.and.deaths.that.is.compiled.by.the.Registrar.General.of.Canada.

Vitrectomysurgical.procedure.that.uses.an.instrument.that.cuts.and.removes.the.vitreous.liquid.of.the.eye.and.replaces.the.liquid.with.saline.or.another.fluid..Typically.used.in.the.setting.of.vitreous.hemorrhage.

References1. Last JM. A Dictionary of Epidemiology (2nd edition)/

Oxford University Press, 1988, Toronto.

2. Wyngaarden JB, Smith LH (eds). Cecil Textbook of Medicine (18th edition). WB Saunders, 1988, Toronto.

3. Tang TA, Secic M. How to Report Statistics in Medicine. Annotated Guidelines for Authors, Editors, and Reviewers. American College of Physicians; Philedelphia: 1997. ISBN: 0-9131126-44-4.

4. Dawson-Suanders B, Trapp RG. Basic and Clinical Biostatistics. Appleton and Lang: Norwalk, Conn. 1990.

5. Hennekens CH, Buring JE. Epidemiology and Medicine. Mayrent SL (Ed)., Little, Brown and Company; Boston, Mass 1987

6. Institute for Clinical Evaluative Sciences. Diabetes in Ontario: An ICES Practice Atlas. 2003. Ontario, Institute for Clinical Evaluative Sciences.

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