Prevalence and Risk Factors of COPD in Karachi, Pakistan: Findings from the Adult Asthma Study-Karachi

Abstract

Background/Aim: Limited data is available regarding burden and risk factors of COPD from developing countries through community based epidemiological assessment comprising spirometry. So to determine the prevalence and risk factors of COPD among adult population of Karachi, Pakistan. Methods: A multi-stage, community-based cross-sectional survey was conducted from May 2014-August 2015 comprising of 1630 adult (≥ 18 years) participants from 75 randomly selected (out of 9400) clusters in Karachi. From each cluster, 25 households were selected randomly and all eligible participants were recruited. Data was collected through questionnaire-based interviews in Urdu, consisting of respiratory health related questions (American Thoracic Society questionnaire; ATS-DLD 78A), socio-demographic characteristics and risk factors for asthma. Pre and post-bronchodilator spirometry was performed according to the ATS criteria. COPD was defined as a post-bronchodilator FEV1/FVC ratio < 0.70 according to the GOLD criteria. Results: Among 930 participants with acceptable spirometry we found the overall prevalence of COPD to be 10.9% (n=101; 95%CI: 8.9-12.8). Among them, the prevalence was 19.4% (n=78; 95%CI: 15.5-23.2) among adults aged 40 and above. Out of 101 participants having COPD, 20.8% have mild, 59.4% have moderate, 18.8% have severe and 1% have very severe disease according to the GOLD criteria of airflow limitation severity in COPD. Risk of COPD was increased with increasing age (AOR: 5.2, 95%CI: 3.1-8.5), increase in pack years of smoking (AOR: 3.3, 95%CI: 1.8-5.9) and among participants reporting history of allergies (AOR: 2.2, 95% CI: 1.4-3.4). Risk of COPD was decreased among those categorized as white collar employees compared to those not working or unemployed (AOR: 0.5, 95% CI: 0.3-0.9). Conclusions: This study provides evidence through robust epidemiological assessment regarding the actual burden of COPD among adults in Pakistan. Targeted preventive measures should be taken to reduce smoking habit and promote better environmental conditions at work places.