Body composition phenotypes linked to physical function in patients with COPD

An association exists between body composition phenotypes and physical function in patients with chronic obstructive pulmonary disease (COPD), with sarcopaenic-obese (SO) patients being the most impaired, a study has shown.

Based on the 10th and 90th percentiles of sex-age-body mass index–specific reference values for fat-free and fat mass indexes, 270 stable COPD patients were categorized into the following groups: normal body composition (NBC), obese, sarcopaenic and SO. The investigators evaluated the patients’ exercise capacity, peripheral and respiratory muscle strength, physical activity, dyspnoea severity, functional status, and symptoms of anxiety and depression.

Of the patients, 39 percent were classified as NBC, 13 percent obese, 21 percent sarcopaenic and 27 percent SO. Six-minute walk test (6MWT) was lower in SO compared with NBC patients (p<0.05). Muscle strength was worse in sarcopaenic and SO groups compared with NBC (p<0.05).

Sarcopaenic patients spent more time in moderate-to-vigorous physical activity than all the other groups (p<0.05) and less sedentary time than NBC and obese patients (p<0.05). No differences were observed in terms of dyspnoea severity, functional status, and symptoms of anxiety and depression (p>0.16).

Furthermore, sarcopaenic and SO groups had 7.8 (95 percent confidence interval [CI], 1.6–37.7) and 9.5 (95 percent CI, 2.2–41.7) times higher likelihood of having a 6MWT ≤350 m.

“Abnormal body composition is an independent determinant of COPD outcomes,” the investigators said. “To date, it is already known that patient stratification into body composition phenotypes are associated with important outcomes, such as exercise capacity and inflammation, but there are no data comparing physical activity and muscle strength among these phenotypes.”