Presentation on theme: "Epidemiology of Airway Diseases-Asthma and COPD in India"— Presentation transcript:
1 Epidemiology of Airway Diseases-Asthma and COPD in India S. K. JindalDepartment of Pulmonary MedicinePostgraduate Institute of Medical Education and ResearchChandigarh, India
2 Prevalence of C.R.D. Global Estimates Ch Resp DisYearPrevalence (Million)Asthma2004300COPD200080Allergic rhinitis2006400Others> 50S.A.S.> 100Bousquet et al, ERJ 2007
3 Global Burden of Asthma Currently: Around 300 m. patientsExpected by 2025: 100 m. additionalLoss of DALYs: About 15 m./year(around 1% of all DALYs lost)Mortality: Accounts for in every 250 deathsEconomic 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 (%) CountryAustraliaN.ZealandBelgiumEnglandGermanySpainFranceU.S.ItalyGreeceSwitzerlandTristan da CunhaCurrent25-4Ever12107356RecentWheeze2830172214916AHR36271847Atopy443534422624
6 Adult* Asthma in Asia Prevalence Rate**(%) China 0.67 – 1.39 Hong Kong – 8.0JapanSingapore – 9.0South Korea 10 – 12.1Taiwan – 6.0Thailand – 10.1Range – 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 methodologyChoi et al APSAR 2004
7 All cause Ranking of Burden of COPD Global Burden of Disease Study Cause of death 6th 3rdDALYsWorldwide 12th 5thDeveloped regions 9thDeveloping regions 4thMurray & Lopez, Lancet 1997
8 Prevalence studies on asthma from India Study PopulationAge (yrs)Definition / MethodologyPrevalence (%)RegionGroupNo.1.Viswanathan (1966)North (P)Urban15805All agesSymptoms on interview1.8Children2.Shah (2000)MulticentricSchools371713169713-146-7Self reported, (ISAAC)3.74.53.Awasthi (2004)North (L)3000do3.32.34.Mistry (2004)North ( C)575Q. wheezing12.55.Chakravarthy (2002)South (TN)Field855< 12Q.Diagnosed asthma56.Chhabra (1998)North (D)26094-17Q; Current11.67.Paramesh (2002)South (B)65506-1516.68.Gupta (2001)North (C )90909-20IUATLD based validated QAdults9.Chowgule (1998)West (M)231320-44ECRHS Q3.510.Jindal (2000)201618 - > 70Validated Q2.811.Aggarwal (2006)73605> 152.4B = 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
9 Validated questionnaire A summary of important field studies from India on prevalence of CB/COPD published in last 30 yearsAuthorsPopulation groupAge (Yrs)Subject No. M FMethod of diagnosisPrevalenceM F1Joshi et al (1975)Punjab (Ind)17-64427Questionnaire2Bhattacharya et al (1975)U.P.(R)30-70+6295113Thiruvengadam et al (1977)Madras city (U)5-60+408409Interview4Vishwanathan & Singh (1977)Delhi (U)5-945524415Radha et al (1977)New Delhi (U)3-60+10871011Questionnaire & PEF6Nigam et al (1982)U.P. (R)20-70+7756497Malik SK (1986)Chandigarh (U)15-65+212122518Jindal SK (1993)Punjab (U)15-70+147513299Ray et al (1995)Tamil Nadu (R )30+4857508910Jindal et al (2006)Multicentric*>=351821717078Validated questionnairePEF = Peak Expiratory Flow; U = Urban; R = Rural; * Bangalore, Chandigarh, Delhi, Kanpur
10 Variations in prevalence Depend upon differences in:Definition of disease used in the studyStudy designsSampling methodsUse of study-instrumentsCollection, recording and analysis of dataInterpretation of resultsExtraneous factors: Expertise & errorsTrue differences: Ethnic, geographical, seasonal, environmental etc.
12 INSEARCH Study Population (Phase II) CentreRuralUrbanTotalMaleFemaleAhmedabad606859453074300018087Berhampur613860391434141415025Bikaner547547552690243115351Chennai347254362320377315001Guwahati537448232573223215002Kolkata451542441828194112528Mumbai368238433416300113942Mysore477843472960293215017Nagpur520948652555245015079Secunderabad233922074546Shimla572550832138205715003Trivandrum44474548289531041499454883539283022230542169575
13 INSEARCH Sampling & Methodology Two stage stratified sampling systemFirst 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 subjects was calculated to be required to give a 95% C.I of ±0.3% for a prevalence of 3 %.Questionnaire AdministrationThe 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 consideredAsthma definitionAny 1 of: (a) whistling sound from the chest or(b) Early morning chest tightness.ANDAny 1 of: (a) attack of asthma .(b) physician diagnosis of asthma in the past or(c) Use of bronchodilatorsChronic Bronchitis DefinitionCough 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.
15 Statistical analyses Questionnaire pre-testing Group comparisons Test-retest methodSplit-half methodGroup comparisonsChi-square test (categorical variables)Student’s t-test (scalar variable)Univariate and multivariate logistic regression analyses for Odds Ratios (OR) and 95% Confidence IntervalsNational burden estimates – based on age-standardized prevalence estimates based onCensus 2011.
16 Results: I. Sample 1,69,575 individuals surveyed Urban - 60, Rural - 1,08,811Men – 85, 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 %Chronic bronchitis (CB) %Smoking Men %Women %Any respiratory Symptom %Total patient estimates(as per 2011 census):Asthma : million (>15 years)CB : million (>35 years)
18 Asthma Prevalence in India (INSEARCH) UrbanRural
23 ETS Exposure in Asthma No Yes ED visits 0.6 0.82* HospitalisationAc. episodes *Parenteral BD *Work absence (wks) *Steroid use (wks) *BD use (wks)*p < 0.01(Jindal et al, Chest 1994)
24 Environmental tobacco smoke exposure and asthma Aggravation and occurrence of increased prevalence of respiratory symptomsBronchial hyper-responsiveness in adultsAggravation of asthma symptomsPrecipitation of acute episodesRisk factor for development of asthma (both children and adults)
25 Active smoking in asthma in adults Increased bronchial responsivenessFrequent bronchial irritation symptomsIncreased sensitization to occupational agentsAggravation of acute episodesAssociation with asthma severityRisk factor for asthma ?Exaggerated decline in lung functionsRole in development of fixed airway obstruction and COPD ?
32 Health costs on Smoking and COPD Annual cost of management of COPD per patient*Expenditure on smoking Rs. 1340Direct costs: Patient Rs. 2259work absence Rs. 410Indirect losses Rs.11454*Comprised ~ 1/3 of average income of patientICMR Report, Jindal et al )Families with one (or more) smoker membershad significantly higher health related expenditure, work and school absenteeism and number of illnessesJindal et al, NMJI 2005
33 ConclusionsThe 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 SpirometryNo specific terms for asthma (vs COPD/ CB) in Indian vernacular languagesGPs do not often differentiate between asthma and COPDInhalers and bronchodilators are commonly used/ abused for nonspecific cough/ breathlessnessThe term “asthma” is interpreted differently in cross-cultural comparisons(Sunyer et al, AJRCCM 2000)5. Confounding (bronchiectasis, CB, TB)