Late-breaking abstract: HRCT comparisons of tobacco smoking (TS-COPD) and biomass smoke induced COPD (BS-COPD) phenotypes from an Indian rural setting

Although biomass smoke associated COPD (BS- COPD) is highly prevalent in India and other developing countries, there is paucity of knowledge whether this COPD is morphologically similar or different from tobacco-smoke associated COPD (TS-COPD). Aim: To compare lung-HRCT patterns of BS-COPD with that of TS-COPD and healthy subjects. Method: Inspiratory and expiratory axial HRCT images were obtained from 42 BS-COPD, 38 TS-COPD, 20 healthy biomass exposed ( BS-Healthy) and 14 Healthy-smokers (TS-Healthy) subjects from a rural setting in India. Lung abnormalities were evaluated at the parenchymal and airway levels using visual semi-quantitative scoring of HRCT morphology by two independent experienced radiologist. The parenchymal patterns were scored at a lobar level to the nearest 5%, and the airways abnormalities were graded on a four point scale. Results: Compared to TS-COPD, subjects with BS-COPD had significantly lower mean sum emphysema scores (265.±343 vs 40±70, p 0.05). The Mean sum emphysema scores and LAA scores amongst TS-Healthy and BS-healthy were significantly lower than TS-COPD and BS-COPD ( both p