Objective: To determine the prevalence of asthma in a group of obese adult candidates for bariatric surgery and to evaluate the severity of asthma in this group of patients. Methods: This was a cross-sectional study involving 363 obese adults (body mass index ≥ 35 kg/m2) evaluated by a pulmonologist, using clinical evaluation as a diagnostic tool for asthma. All patients underwent clinical evaluation and spirometry and were divided into two groups (asthma and control). The patients with asthma were stratified by the severity of asthma. Results: The prevalence of asthma in the obese population studied was 18.5% (95% CI: 14.5-22.4). That prevalence was 20.4% (95% CI: 16.2-24.5) and 13.7% (95% CI: 10.1-17.2) in the women and the men, respectively. Asthma symptoms in the last twelve months were present in 8.0% (95% CI: 5.2-10.7), and the initial manifestation of asthma symptoms occurred during childhood/adolescence in 17.4% (95% CI: 13.5-21.3). In the asthma group, intermittent asthma was present in 29 patients (43.3%), mild persistent asthma in 7 (10.4%), moderate asthma in 25 patients (37.3%), and severe persistent asthma in 6 (9.0%). Conclusions: Using clinical evaluation as the diagnostic criterion, we found the prevalence of asthma to be high in this group of obese adults. Asthma was more common in females, and the initial manifestation of asthma symptoms more commonly occurred during childhood/adolescence. The severity of asthma in this group of obese adults was within the range of mean values predicted for the general population. Intermittent asthma, mild persistent asthma, and moderate persistent asthma predominated.

Keywords: Asthma; Cross-sectional studies; Spirometry; Respiratory function tests; Obesity, morbid.