COPET study findings regarding the clinical relevance of biomass exposure as an etiotype in COPD.

Purpose: The finding that COPD can also develop in non-smokers has led to further investigations of etiologic causes other than smoking. This study evaluated the relationship between tobacco smoking and/or biomass-burning smoke exposure (BBS) and the demographic, clinical, and prognostic characteristics of individuals with COPD.

Methods: A total of 1129 stable COPD patients from the COPET study were retrospectively analyzed. The patients were divided into three groups: the COPD-B group (n = 52), which included patients who were solely BBS; the COPD-C group (n = 634), which included patients who exclusively tobacco smoking; and the COPD-BC group (n = 443), which included patients with both BBS and tobacco smoking.

Results: The average age of the patients was 65.8 ± 9.1 years, and 87.4% of them were men. In the COPD-B group, the following factors were significantly greater compared to the COPD-C and COPD-BC groups: age (p = 0.001), BMI (p = 0.001), percentage of female patients (p < 0.001), FEV1/FVC ratio (p = 0.014), eosinophil count (p < 0.001), ADO score (p < 0.001), and the proportion of patients with frequent exacerbations (p = 0.013). Thorax CT scans showed that the COPD-BC group had a greater incidence of bronchiectasis and emphysema than the COPD-B and COPD-C groups (p< 0.001).

Conclusion: This study highlights significant clinical and radiological differences among COPD patients based on tobacco smoking and BBS, which may substantially impact COPD outcomes, including exacerbations and prognosis.