Differences in COPD: Smokers versus non smokers

Introduction: in all epidemiological studies there are always a proportion of never smoking COPD patients. This study aims to characterize the difference between smokers and never smokers in COPD. Methods: we enrolled COPD patients attending pulmonary care in a tertiary hospital. Never smokers had a history of less than 0.1 pack years. Anthropometric measures, spirometry, plethysmography, 6MWT and blood tests were performed. Results: we enrolled 51 non smokers and 165 smokers with COPD. There was no difference in age or FEV1% between both groups. BMI and fat free mass were statistically higher in the non smoker COPD group. The IC/TLC, DLCO, walked distance in the 6MWT and the BODE index were also significantly higher in this group. However, comorbidities, measured by both the Charlson and the COTE index, were significantly lower in the non smoking COPD group. Conclusion: in spite of having the same diagnosis, the non smoker group has a milder disease than the smoker group. This fact hints the possibility of two different clinical entities.