Body composition, pulmonary function tests, exercise capacity, and quality of life in chronic obstructive pulmonary disease patients with obesity

Purpose of the study: Larger proportions of chronic obstructive pulmonary disease (COPD) patients are currently overweight or with obesity than underweight, and the combination of COPD and obesity is increasing. The purpose of this study was to investigate differences in the body composition, pulmonary function tests, exercise capacity, and health-related quality of life among normal weight, overweight, and obese patients with COPD. Study design: A total of 514 patients with COPD were included in the study. According to the World Health Organization criteria for body mass index, the patients were classified as normal weight, overweight, and obese. Evaluations included fat-free mass, fat-free mass index, phase angle, pulmonary function tests, and 6-minute walk test. Dyspnea was assessed using the modified Medical Research Council dyspnea scale, and the health-related quality of life was evaluated using COPD Assessment Test and St. George's Respiratory Questionnaire. Values were compared among the three groups. Results: There were 315 male and 199 female patients, with a mean age of 66.7 +/- 8.4 years. Fat-free mass, fat-free mass index, and phase angle values were significantly higher in COPD patients with obesity than in other patients (P < .001, P < .001, P < .001). Forced expiratory volume in 1 s, forced expiratory volume in 1 s/forced vital capacity, and diffusing capacity of lung for carbon monoxide value in pulmonary function tests were significantly higher in COPD patients with obesity than in other patients (P = .046, P < .001, P < .001), while the forced vital capacity values were similar in all groups. Exercise capacity (6-min walk test distance), dyspnea symptoms (modified Medical Research Council scale), and health-related quality of life (COPD Assessment Test and St. George's Respiratory Questionnaire) did not differ significantly between groups. Conclusions: According to our study, obesity has no negative effect on pulmonary function tests, dyspnea perception, exercise capacity, and health-related quality of life.