Prevalence of Undiagnosed Chronic Obstructive Pulmonary Disease among Smokers and Biomass-Fuel-Exposed Adults: A Multicenter Community-Based Study

Abstract

Objective: To determine the prevalence of previously undiagnosed chronic obstructive pulmonary disease and its associated factors among adults exposed to cigarette smoke or household biomass fuel in Pakistan.

Methods: This multicenter, community-based cross-sectional study included 220 adults aged ≥40 years recruited from community outreach sites affiliated with participating tertiary-care institutions across Pakistan between January and December 2025. Eligible participants had smoked at least 10 pack-years, used biomass fuel for at least 10 years, or experienced both exposures. Individuals with previously diagnosed chronic obstructive pulmonary disease were excluded. Symptoms and exposures were recorded through structured interviews. Pre-bronchodilator and post-bronchodilator spirometry was performed according to accepted standards. Undiagnosed chronic obstructive pulmonary disease was defined as a post-bronchodilator FEV₁/FVC ratio below 0.70.

Results: Spirometry confirmed previously undiagnosed chronic obstructive pulmonary disease in 41 participants, giving a prevalence of 18.6% (95% CI: 13.7–24.4%). Prevalence was 15.9% among smokers, 15.9% among biomass-exposed adults and 28.0% among participants with dual exposure. Most detected cases had mild or moderate airflow limitation. Older age, dual exposure, exposure lasting at least 20 years, chronic cough and exertional dyspnea remained independently associated with disease.

Conclusion: Nearly one in five high-risk adults had undiagnosed chronic obstructive pulmonary disease. Community-based symptom assessment followed by targeted spirometry could identify disease earlier within resource-constrained Pakistani healthcare settings.