Spatial Epidemiology of COPD in Delhi, India

Introduction Chronic obstructive pulmonary disease (COPD) and bronchial asthma are the most common chronic respiratory illnesses. COPD is one of the three most common causes of death worldwide. The main burden of mortality from COPD is seen in Latin America, sub-Saharan Africa, India, China, and South-East Asia. Absence of true prevalence values and mortality burden hinder planning and operationalization of public health interventions for prevention, control, and treatment of the disease. Further, the aggregated value of prevalence estimates calculated for a whole city or a larger geographical area does not provide the location of patients and presence of locally prevalent risk factors. The objective of this study was to understand the spatial distribution of COPD in a large, highly polluted city of a developing country. Materials and Methods A cross-sectional community-based study was conducted in the National Capital Territory of Delhi (NCTD). All surveyed households were geocoded. GOLD screening criteria and pulmonary function tests using portable digital spirometer were used for diagnosis of COPD. Results Results are presented as a series of maps depicting spatial epidemiology. Overall prevalence rate was 9.8/1,000 population. Highest prevalence was seen in industrial area. Most of the spatial hotspots were seen in industrial and slum areas. Similarly, Kernel density was also highest in industrial area. Conclusion In the city of NCTD, we found the COPD being distributed in all types of habitations but spatial distribution helped us understand clustering of cases and compare prevalence rates in subunits of residential clusters within a metropolitan city.