Distribution of clinical phenotypes in patients with chronic obstructive pulmonary disease caused by biomass and tobacco smoke.

Introduction: Exposure to biomass smoke is a risk factor for chronic obstructive pulmonary disease (COPD). It is unknown whether COPD caused by biomass smoke has different characteristics to COPD caused by tobacco smoke.
Objective: To determine clinical differences between these two types of the disease.
Methods: Retrospective observational study of 499 patients with a diagnosis of COPD due to biomass or tobacco smoke. The clinical variables of both groups were compared.
Results: There were 122 subjects (24.4%) in the biomass smoke group and 377 (75.5%) in the tobacco smoke group. In the tobacco group, the percentage of males was higher (91.2% vs 41.8%, P<.0001) and the age was lower (70.6 vs 76.2 years, P<.0001). Body mass index and FEV1% values were higher in the biomass group (29.4±5.7 vs 28.0±5.1, P=.01, and 55.6±15.6 vs 47.1±17.1, P<.0001, respectively). The mixed COPD-asthma phenotype was more common in the biomass group (21.3% vs 5%, P<.0001), although this difference disappeared when corrected for gender. The emphysema phenotype was more common in the tobacco group (45.9% vs 31.9%, P=.009). The prevalence of the chronic bronchitis and exacerbator phenotypes, the comorbidity burden and the rate of hospital admissions were the same in both groups.
Conclusion: Differences were observed between COPD caused by biomass and COPD caused by tobacco smoke, although these may be attributed in part to uneven gender distribution between the groups.
(Copyright © 2013 SEPAR. Published by Elsevier Espana. All rights reserved.)