Epidemiology of Airway Diseases-Asthma and COPD in India

S. K. JindalDepartment of Pulmonary Medicine

Postgraduate Institute of Medical Education and ResearchChandigarh, India

Prevalence of C.R.D. Global Estimates

Ch Resp Dis Year Prevalence (Million)

•Asthma 2004 300

•COPD 2000 80

•Allergic rhinitis 2006 400

•Others 2006 > 50

•S.A.S. > 100

Bousquet et al, ERJ 2007

Global Burden of Asthma

• Currently: Around 300 m. patients• Expected by 2025: 100 m. additional• Loss of DALYs: About 15 m./year

(around 1% of all DALYs lost)• Mortality: Accounts for in every 250 deaths• Economic costs: Include direct treatment

expenditure and indirect losses due to absenteeism, disability and health-care management.

Global Initiatives in Epidemiology

Asthma: ISAAC (International study on

Asthma and Allergies in Children)

ECRHS (European Community Respiratory Health Survey)

COPD: BOLD (Burden of Obstructive Lung

Disease)

PLATINO (COPD Prevalence in five

Latin American Cities)

Global Adult Asthma Prevalence (%)

Country

AustraliaN.ZealandBelgiumEnglandGermanySpainFranceU.S.ItalyGreeceSwitzerlandTristan da Cunha

Current

25-4---------

Ever

12107

123447437

56

RecentWheeze

28--

30172214259

16--

AHR

36274

161410181810-

1647

Atopy

5644-

283534354226252447

Adult* Asthma in AsiaPrevalence Rate**(%)

China 0.67 – 1.39Hong Kong 3.9 – 8.0Japan 3.6Singapore 0.9 – 9.0South Korea 10 – 12.1Taiwan 2.4 – 6.0Thailand 2.91 – 10.1Range 0.67 – 12.1

* >15 year old** Figures reported the collective range of period prevalence of asthma

ranging from 3 months to 1 year rates depending on the variation in study methodology

Choi et al APSAR 2004

All cause Ranking of Burden of COPDGlobal Burden of Disease Study

1990 2020

• Cause of death 6th 3rd

• DALYs

Worldwide 12th 5th

Developed regions 9th

Developing regions 4th

Murray & Lopez, Lancet 1997

Prevalence studies on asthma from IndiaStudy Population Age (yrs) Definition /

Methodology Prevalence

(%)Region Group No.

1. Viswanathan (1966) North (P) Urban 15805 All ages Symptoms on interview

1.8

Children

2. Shah (2000) Multicentric Schools 3717131697

13-146-7

Self reported, (ISAAC)

3.74.5

3. Awasthi (2004) North (L) Schools 3000 13-146-7

do 3.32.3

4. Mistry (2004) North ( C) Schools 575 13-14 Q. wheezing 12.5

5. Chakravarthy (2002) South (TN) Field 855 < 12 Q.Diagnosed asthma

5

6. Chhabra (1998) North (D) Schools 2609 4-17 Q; Current 11.6

7. Paramesh (2002) South (B) Schools 6550 6-15 16.6

8. Gupta (2001) North (C ) Schools 9090 9-20 IUATLD based validated Q

2.3

Adults

9. Chowgule (1998) West (M) Field 2313 20-44 ECRHS Q 3.5

10. Jindal (2000) North (C ) Field 2016 18 - > 70 Validated Q 2.8

11. Aggarwal (2006) Multicentric Field 73605 > 15 Validated Q 2.4B = Bangalore; C = Chandigarh; D = Delhi; IUATLD = International Union Against Tuberculosis & Lung Disease; ISAAC = International Study on Allergies and Asthma in Children; L = Lucknow; M = Mumbai; P = Patna; Q = Questionnaire; ECRHS = European Community Respiratory Health Survey; TN = Tamil Nadu

A summary of important field studies from India on prevalence of CB/COPD published in last 30 years

Authors Population group

Age (Yrs)

Subject No. M F

Method of diagnosis

Prevalence M F

1 Joshi et al (1975) Punjab (Ind) 17-64 427 0 Questionnaire 12.5 -

2 Bhattacharya et al (1975)

U.P.(R) 30-70+ 629 511 Questionnaire 6.7 4.5

3 Thiruvengadam et al (1977)

Madras city (U) 5-60+ 408 409 Interview 1.9 1.2

4 Vishwanathan & Singh (1977)

Delhi (U) 5-94 552 441 Questionnaire 8.0 4.3

5 Radha et al (1977) New Delhi (U) 3-60+ 1087 1011 Questionnaire & PEF

8.1 4.6

6 Nigam et al (1982) U.P. (R) 20-70+ 775 649 Interview 9.0 4.5

7 Malik SK (1986) Chandigarh (U) 15-65+ 2121 2251 Questionnaire & PEF

5.5 2.9

8 Jindal SK (1993) Punjab (U) 15-70+ 1475 1329 Questionnaire & PEF

5.0 2.7

9 Ray et al (1995) Tamil Nadu (R ) 30+ 4857 5089 Questionnaire 4.1 2.5

10 Jindal et al (2006) Multicentric* >=35 18217 17078 Validated questionnaire

5.0 3.2

PEF = Peak Expiratory Flow; U = Urban; R = Rural; * Bangalore, Chandigarh, Delhi, Kanpur

Variations in prevalence

Depend upon differences in:•Definition of disease used in the study•Study designs•Sampling methods•Use of study-instruments•Collection, recording and analysis of data•Interpretation of results•Extraneous factors: Expertise & errors•True differences: Ethnic, geographical, seasonal, environmental etc.

Bikaner

Ahmedabad

Mumbai

BangaloreChennai

Secunderabad

Nagpur Kolkata

Kanpur

Chandigarh

Trivandrum

Guwahati

Delhi

Shimla

Berhampur

Mysore

2012

INSEARCH Study Population (Phase II)

CentreRural Urban

TotalMale Female Male Female

Ahmedabad 6068 5945 3074 3000 18087

Berhampur 6138 6039 1434 1414 15025

Bikaner 5475 4755 2690 2431 15351

Chennai 3472 5436 2320 3773 15001

Guwahati 5374 4823 2573 2232 15002

Kolkata 4515 4244 1828 1941 12528

Mumbai 3682 3843 3416 3001 13942

Mysore 4778 4347 2960 2932 15017

Nagpur 5209 4865 2555 2450 15079

Secunderabad 0 0 2339 2207 4546

Shimla 5725 5083 2138 2057 15003

Trivandrum 4447 4548 2895 3104 14994

Total 54883 53928 30222 30542 169575

INSEARCH Sampling & Methodology Two stage stratified sampling system

– First stage – Village/Urban area (30 clusters per centre)– Second stage – Houses (100 Houses per cluster)

•All residents of the selected houses aged ≥15 years were interviewed.

•Two additional attempts were made to contact an individual in case of non availability at the first visit.

•A Sample size of 12421 subjects was calculated to be required to give a 95% C.I of ±0.3% for a prevalence of 3 %.

Questionnaire Administration The Questionnaire was administered by the field staff who were trained for the same.

•Internal Quality assurance : 10% of the households visited by the study site supervisor randomly.

•External Quality assurance : Periodic monitoring visits by the officers from the controlling centre ( Chandigarh)

Questionnaire & Definitions

• Bronchial Symptom Questionnaire (1984) developed by International Union Against Tuberculosis and Lung Diseases (IUALTD). Symptoms in the preceding 12 months were considered

• Asthma definition Any 1 of: (a) whistling sound from the chest or (b) Early morning chest tightness.AND Any 1 of: (a) attack of asthma . (b) physician diagnosis of asthma in the past or (c) Use of bronchodilators

• Chronic Bronchitis Definition Cough with expectoration for ≥ 3 mths for 2 consecutive years.

• Objective measurements such as spirometry and bronchial hyper reactivity were not measured.

• Diagnosis based only on questionnaire.

Statistical analyses1. Questionnaire pre-testing

• Test-retest method• Split-half method

2. Group comparisons• Chi-square test (categorical variables)• Student’s t-test (scalar variable)• Univariate and multivariate logistic regression

analyses for Odds Ratios (OR) and 95% Confidence Intervals

3. National burden estimates – based on age-

standardized prevalence estimates based on Census 2011.

Results: I. Sample

• 1,69,575 individuals surveyed Urban - 60,764 Rural - 1,08,811

Men – 85,105 Women – 84,470

• % of surveyed individuals to the total eligible individuals in the households. Urban – 98.6% Rural – 97.6%

II. National Prevalence (Adults)

Asthma - 2.04% Chronic bronchitis (CB) - 3.58% Smoking - Men - 18.5% Women - 0.5% Any respiratory Symptom - 8.5%

Total patient estimates • (as per 2011 census):

Asthma : 17.23 million (>15 years) CB : 14.84 million (>35 years)

Asthma Prevalence in India (INSEARCH)

Urban Rural

Chronic Bronchitis (INSEARCH)

Cough and phlegm for last three years (age >40 years)

15% 10% 5% 0 5% 10% 15%

Trivandrum

Shimla

Secunderabad

Nagpur

Mysore

Mumbai

Kolkata

Guwahati

Chennai

Bikaner

Berhampur

Ahmedabad

MenWomen

Urban Rural

Risk factors - Asthma

Risk Factors - CB

Smoking, ETS & Asthma (Insearch)Multiple Logistic Regression

ETS Exposure in AsthmaNo Yes

• ED visits 0.6 0.82*• Hospitalisation 0.33 0.34• Ac. episodes 0.6 1.32*• Parenteral BD 6.0 8.6*• Work absence (wks) 3.0 3.6*• Steroid use (wks) 8.6 11.3*• BD use (wks) 36.3 38.3

*p < 0.01

(Jindal et al, Chest 1994)

Environmental tobacco smoke exposure and asthma

1. Aggravation and occurrence of increased prevalence of respiratory symptoms

2. Bronchial hyper-responsiveness in adults

3. Aggravation of asthma symptoms

4. Precipitation of acute episodes

5. Risk factor for development of asthma (both children and adults)

Active smoking in asthma in adults

1. Increased bronchial responsiveness

2. Frequent bronchial irritation symptoms

3. Increased sensitization to occupational agents

4. Aggravation of acute episodes

5. Association with asthma severity

6. Risk factor for asthma ?

7. Exaggerated decline in lung functions

8. Role in development of fixed airway obstruction and COPD ?

Exposure to Solid-Fuel Combustion & Asthma(Insearch) Multiple Logistic Regression

Aspergillin hypersensitivity and/or ABPA in Bronchial Asthma

(Prospective studies)

Study Hypersensitivity ABPA

(n/N)

1. Eaton (2000) 47/255 9/35

2. Kumar (2000) 47/200 32/200

3. Maurya (2005 30/105 8/105

4. Agarwal (2007) 291/755 155/755

5. Prasad (2008) 74/244 18/244

6. Agarwal (2010) 87/242 54/242

Agarwal R, ABPA(Text Book PCCM, 2011)

Aspergillus hypersensitivity in asthma

Agarwal et al. Int J Tuberc Lung Dis 2009; 13: 936–944

ABPA in asthma

Agarwal et al. Int J Tuberc Lung Dis 2009; 13: 936–944

Economic burden of asthma (Rs in crores)

Year Chronic Acute Total

1996 960.05 167.07 1127.12

2001 1543.74 267.63 1811.37

2006 2294.73 388.84 2683.57

2011 3197.60 528.84 3726.44

2016 4180.35 672.52 4852.86 Murthy & Sastry NCMH Background Papers

Murthy & Sastry. NCMH Background Papers

Economic Burden of Asthma

Health costs on Smoking and COPD

1. Annual cost of management of COPD per patient*

Expenditure on smoking Rs. 1340Direct costs: Patient Rs. 2259

work absence Rs. 410Indirect losses Rs.11454

*Comprised ~ 1/3 of average income of patient ICMR Report, Jindal et al 1993-98)

2. Families with one (or more) smoker members

had significantly higher health related expenditure, work and school absenteeism and number of illnesses

Jindal et al, NMJI 2005

Conclusions• The total population prevalence estimate of asthma

and CB in adults account for over 32 million patients for the projected 2011 population of around 415 million. Cumulative prevalence increases with age.

• Smoking, Environmental Tobacco Smoke and Biomass combustion exposures are important & preventable risk factors for asthma as well as CB.

• Allergic Bronchopulmonary Aspergillosis is a common problem seen in asthma.

• There is an enormous economic burden from both disorders. Guideline-directed management is significantly cheaper and cost-effective.

Symptom-based diagnosis - Limitations

1. Lack of objective measurements like Spirometry

2. No specific terms for asthma (vs COPD/ CB) in Indian vernacular languages

3. GPs do not often differentiate between asthma and COPD

4. Inhalers and bronchodilators are commonly used/ abused for nonspecific cough/ breathlessness

5. The term “asthma” is interpreted differently in cross-cultural comparisons

(Sunyer et al, AJRCCM 2000)

5. Confounding (bronchiectasis, CB, TB)

THANKS