Geographic distribution of chronic obstructive pulmonary disease prevalence in Africa, Asia and Australasia

OBJECTIVE: To visualise spatial data on chronic obstructive pulmonary disease (COPD) prevalence in Africa, Asia and Australasia using a Geographic Information System (GIS) inverse distance weighted (IDW) interpolation technique. DESIGN: Prevalence rates from population surveys on individuals aged ≥40, with spirometry-confirmed COPD, were searched systematically. The prevalence observed in 59 selected surveys and the geographic coordinates of the places where they were conducted informed a GIS computer programme. The prevalence was represented by an ascending chromatic scale (blue-green-yellow-orange-brown-red) in the GIS maps. RESULTS: IDW-interpolation GIS maps were obtained of all the geographic areas investigated, and even from regions lacking data. Areas of high/very high prevalence were found in: Southern Africa and in most of the Central and Eastern Africa regions; in practically all of Central Asia; in the western regions of Southern Asia; in the southern regions of the East European Plain and the West Siberian Plain of Northern Asia; and in the Malay Archipelago. Intermediate prevalence predominated in Oceania and in most of the other regions of Africa and Asia. CONCLUSION: Despite some biases inherent to the interpolation method used in the present study, our approach provided an understandable visual perspective of the COPD prevalence distribution in these geographic regions.