Epidemiology of Airway Diseases-Asthma and COPD in India

1. Epidemiology of Airway Diseases-Asthma and COPD in India S. K. Jindal Department of Pulmonary Medicine Postgraduate Institute of Medical Education and Research Chandigarh, India

2. Prevalence of C.R.D. Global Estimates

3. 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.

4. 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)

5. Global Adult Asthma Prevalence (%)

6. Adult* Asthma in Asia Prevalence Rate**(%) China 0.67 – 1.39 Hong Kong 3.9 – 8.0 Japan 3.6 Singapore 0.9 – 9.0 South Korea 10 – 12.1 Taiwan 2.4 – 6.0 Thailand 2.91 – 10.1 Range 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

7. 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

8. Prevalence studies on asthma from India B = 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

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

10. 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.

11. Shimla Chandigarh Delhi Bikaner Guwahati Kanpur Ahmedabad Kolkata Nagpur Berhampur Mumbai Secunderabad Bangalore Chennai Mysore Trivandrum 2012

12. INSEARCH Study Population (Phase II)

13. 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)

14. 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 mthsfor 2 consecutive years. • Objective measurements such as spirometry and bronchial hyper reactivity were not measured. • Diagnosis based only on questionnaire.

15. Statistical analyses • Questionnaire pre-testing • Test-retest method • Split-half method • 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 • National burden estimates – based on age- standardized prevalence estimates based on Census 2011.

16. 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%

17. 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)

18. Asthma Prevalence in India (INSEARCH) Urban Rural

19. Chronic Bronchitis (INSEARCH) Urban Rural

20. Risk factors - Asthma

21. Risk Factors - CB

22. Smoking, ETS & Asthma (Insearch)Multiple Logistic Regression

23. ETS Exposure in Asthma No 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)

24. Environmental tobacco smoke exposure and asthma • Aggravation and occurrence of increased prevalence of respiratory symptoms • Bronchial hyper-responsiveness in adults • Aggravation of asthma symptoms • Precipitation of acute episodes • Risk factor for development of asthma (both children and adults)

25. Active smoking in asthma in adults • Increased bronchial responsiveness • Frequent bronchial irritation symptoms • Increased sensitization to occupational agents • Aggravation of acute episodes • Association with asthma severity • Risk factor for asthma ? • Exaggerated decline in lung functions • Role in development of fixed airway obstruction and COPD ?

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

27. Aspergillin hypersensitivity and/or ABPA in Bronchial Asthma (Prospective studies)

28. Aspergillus hypersensitivity in asthma Agarwal et al. Int J Tuberc Lung Dis 2009; 13: 936–944

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

30. 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 • 4180.35 672.52 4852.86 Murthy & Sastry NCMH Background Papers

31. Economic Burden of Asthma Murthy & Sastry. NCMH Background Papers

32. Health costs on Smoking and COPD • Annual cost of management of COPD per patient* Expenditure on smoking Rs. 1340 Direct costs: Patient Rs. 2259 work absence Rs. 410 Indirect losses Rs.11454 *Comprised ~ 1/3 of average income of patient ICMR Report, Jindal et al 1993-98) • 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

33. 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.

34. Symptom-based diagnosis - Limitations • Lack of objective measurements like Spirometry • No specific terms for asthma (vs COPD/ CB) in Indian vernacular languages • GPs do not often differentiate between asthma and COPD • Inhalers and bronchodilators are commonly used/ abused for nonspecific cough/ breathlessness • The term “asthma” is interpreted differently in cross-cultural comparisons (Sunyer et al, AJRCCM 2000) 5. Confounding (bronchiectasis, CB, TB)

35. THANKS