Impact of Early Hypertension Control on CV Events in Adults

with Type 2 Diabetes

Patrick J. O’Connor MD MA MPH1, Gabriela Vazquez-Benitez Ph.D. 1,

Julie A. Schmittdiel Ph.D.2, Emily D. Parker Ph.D. 1, Nicole K. Trower BS1,

Jay R. Desai MPH1 , Karen L. Margolis MD MPH1, David J. Magid MD MPH3

1HealthPartners Research Foundation, Minneapolis, MN;2Kaiser Permanente of Northern California, Oakland, CA3Kaiser Permanente of Colorado, Denver, CO; Division of Research,

Duality of Interest: Dr. O’Connor

• No duality of Interest

• Funded by AHRQ HHSA 290-2005-0033-I

Significance

• About 70% of T2DM patients have hypertension

• Uncontrolled BP control increases risk of both macro and micro complications

• Timing of BP control has not been well studied• Debate between BP < 130/80 versus < 140/90 • Time lag from control to benefit not very well

defined

Design, Study Sites, Data Sources

• Retrospective Cohort Study• 3-HMO sites: KP Colorado, KP Northern

California, HealthPartners• CVRN Hypertension Superset• Years of Data: 2003-2009• Used about 10 Data Tables: demo, vitals, Dx,

Rx, diagnoses, enrollment, utilization, etc.

Study Subjects

• Age 30-74 years• Already have T2DM, then get new-onset HT• No CHD or CeVD at date of HT onset• HT Onset Date= Second of 2+ consecutive

dates with elevated EBP• Must have >1 yr follow up after hypertension

onset; AND >= 2 BP measures within 12 months of HT onset date

Blood Pressure Measures: Within 12 months of HT Onset Date

• Hypertension control status: mean of all (2+) SBP/DBP measures within the first year a.

SBP < 130 AND DBP < 80 b. SBP >= 140, OR DBP >= 90 c. Else SBP 130-139 and DBP 80-89

• Hypertension recognition: was there 1+ HT diagnosis code (401.xx) within first year

• Hypertension treatment initiation: 1+ fills for HT medication within the first year

• Systolic BP at HT onset (mean of 2 SBP measures)

Covariate Definitions

• 10-Year Framingham CV risk score (FRS) (D’Agostino 2008)

• Diabetes Microvascular severity score • Count of common diabetes complications based

on ICD-9 codes (Young, et al @GHC, AJMC 2008)• Risk factors (age, gender, race, BMI, smoking,

HDL, Total Cholesterol)

Outcome Definitions

Major CV events ascertained using inpatient claims data from 1 year after HT onset date to censoring date (mean of 38 months follow-up)

Major CV Events Included:• Acute myocardial infarction (410.xx)• Cerebrovascular event (430.xx-434.xx, 436.xx)

Analysis Plan• Consistency of data across sites was assessed• Age adjusted incident CV event rates in 38

month follow-up period by categories of BP control, HT identification, and HT Treatment within 12 months of HT Onset

• Incidence Rate Ratio of BP control defined as– <130/80 vs. >= 130/80 mmHg– 140/90 vs. >= 140/90 mmHgAdjusting for FRS, micro complication score, and site

Diabetes with Incident hypertension cohort based on study exclusion criteria

Table 1. Characteristics of patients with diabetes and new onset hypertension (HT) classified by BP status in the 12-month

after HT date of onset.*

Characteristic <130/80 mmHg 130-140 /80-90 mmHg

>=140/90 mmHg

Number of Subjects 5158 7409 3098

Mean age at baseline± SD, years 51.210.5 51.210.3 53.010.4

Female 51.3% 42.5% 39.7%

Lipids-Framingham Risk Categories†

<10% 35.0% 29.3% 16.8%

10-19% 36.1% 37.9% 34.8%

20+% 28.9% 32.9% 38.4%

Microvascular diabetes complications at baseline††

None 74.0% 80.5% 80.2%

Mean SBP at onset ± SD, mmHg 133.1 + 8.5 135.9 + 8.5 145.3 + 10.8

Mean SBP w 1 yr HT onset ± SD, mmHg 122.2 + 5.4 131.7 + 5.5 145.9 + 8.4

A1c %

<7% 48.5% 46.6% 44.1%

7-7.9% 20.2% 21.5% 22.3%

8+% 25.5% 26.4% 30.4%

Not Available 5.7% 5.5% 3.2%

Table 2. Rates of hypertension recognition, hypertension treatment initiation and BP control status within 12-months of HT onset in patients with diabetes and incident

hypertension. Incident hypertension was based on two or more consecutive BP measures >= 130/80 mmHg.

Systolic BPStatus at

Time of HTOnset (mmHg)

Number of

Subjects

Percent withHT

Recognition(diagnosis

Code) within12 months of

HT onset

PercentStarted on

HTMedicationsWithin 12Months ofHT onset

Percent with specified BP Status in the 12 month period after date of HT onset*

<130/80 mmHg

130-140/80-90 mmHg

≥140/90 mmHg

<130** 2,821 13.1 25.1 49.5 45.8 4.6

130-139 6,643 21.2 34.7 38.1 52.5 9.4

≥140 6,201 46.1 53.6 19.9 42.4 37.8

Overall 15,665 29.6 40.5 32.9 47.3 19.8

*Based on a median of 4 BP measures per patient in the 12-month period.**Subjects classified as hypertensive with SBP < 130 mmHg had DBP >= 80 mmHg

Table 3. Age adjusted rates of Major CV Events per 1000 person years as a function of baseline BP status, BP control status in the 12 months after hypertension (HT) onset, BP medication initiation in the 12-months after hypertension onset, and hypertension

recognition in the 12 months after hypertension onset.

Characteristics Cerebrovascular Event Acute Myocardial Infarction

Total Major Cardiovascular Event*

2.76(2.34-3.26) 3.37(2.90-3.92) 5.90(5.26-6.62)Mean SBP at HT onset

<130 3.16(2.10-4.76) 2.05(1.24-3.40) 5.10(3.69-7.04)130-139 2.17(1.62-2.90) 2.22(1.67-2.96) 4.27(3.47-5.25)

140+ 2.54(1.95-3.31) 4.34(3.27-5.71) 6.94(5.57-8.64)p-value 0.33 <.0001 .004

Blood pressure status in the first year after HT onset

<130/80 2.11(1.51-2.94) 2.76(2.06-3.71) 4.75(3.80-5.95)130-139/80-89 2.50(1.93-3.23) 2.76(2.16-3.52) 5.02(4.19-6.02)

140+/90+ 3.01(2.17-4.19) 4.32(3.27-5.71) 6.94(5.57-8.64)p-value 0.31 0.03 0.03

HT treatment initiation in the first year

Yes 2.62(2.01-3.42) 3.42(2.70-4.32) 5.77(4.82-6.92)No 2.40(1.90-3.03) 2.89(2.34-3.51) 5.07(4.32-5.96)

p-value 0.60 0.28 0.27HT recognition in the first year

Yes 2.54(1.87-3.45) 3.26(2.48-4.28) 5.46(4.42-6.73)No 2.46(1.98-3.05) 3.03(2.50-3.68) 5.31(4.58-6.15)

p-value 0.86 0.83 0.66

Rates were calculated using Poisson regression model with age centered at the mean of the population; p-values correspond to type 3 likelihood ratio statistics.*Total major cardiovascular events include myocardial infarction, hemorrhagic stroke, and thrombotic stroke.

Rate Ratios (95% CI ) for Cerebrovascular Event (CeVD), Acute Myocardial Infarction (MI) and Total Major Cardiovascular Events (Any) estimated based on mean BP in the 12-month period after hypertension of: (a) above versus below 130/80 mmHg, and

(b) above versus below 140/90 mmHg

Conclusions—1

• BP control to < 140/90 mmHg within 12 months of HT Onset date was associated with significantly lower rates of Total CV Events and MI within a mean f/u period of 38 months.

• BP control to < 130/80 mmHg did not show benefits that were as significant.

• Early BP control within 1 year of HT onset may provide important clinical benefits to patients in a relatively short period of time.

Conclusions—2

• Patients with higher baseline FRS or microvascular complications index (more severe DM) had a greater absolute (but not relative) risk reduction in number of CV events prevented by early BP control.

• However, the difference was not statistically significant

• Larger or longer study needed to fully resolve

Conclusions—3

• Many patients with new onset HT returned to normal BP levels in absence of a HT diagnosis or HT medications.

• It may be that some of this related to lifestyle changes, but other possibilities include:– Accuracy and consistency of BP measures– Need to revise diagnostic criteria for HT to require

more elevated BP readings, or higher BP readings.

More Information?

Please Contact:

Patrick.j.oconnor@healthpartners.com