Impaired Skeletal Muscle in Patients with Stable Chronic Obstructive Pulmonary Disease (COPD) Compared with Non-COPD Patients

PURPOSE: This study was designed to investigate the differences in skeletal-muscle atrophy between patients with stable chronic obstructive pulmonary disease (COPD) and healthy controls; associated factors were also considered. The study comprised selected residents of communities near the First Affiliated Hospital of Soochow University in Suzhou City, East China. PATIENTS AND METHODS: Included in this study were 123 COPD patients and 60 controls. All patients completed spirometry as well as examinations to determine their functional exercise capacity, body composition, and handgrip strength (HGS). RESULTS: COPD patients had less fat-free mass (FFM), a lower FFM index (FFMI), and a lower 6-min walking distance (6MWD) compared with controls (P = 0.007, P = 0.020, and P < 0.001, respectively) (FFMI: 17.59 ± 1.83 vs 18.34 ± 1.64). The HGS of these patients was also lower compared with that of controls (32.88 ± 7.84 vs 35.48 ± 7.42), and HGS tended toward statistical significance (P = 0.064, respectively). In multivariate analysis, age (β = −0.107, P < 0.001), gender (β = 0.212, P < 0.001), body mass index (BMI) (β = 0.462, P < 0.001), FEV(1)% (β = 0.108, P = 0.009), and calf circumference (CC) (β = 0.457, P < 0.001) were significantly associated with FFMI. CONCLUSION: Impaired skeletal muscle mass was more common in COPD patients than in controls. Multiple regression analysis showed that CC may be used to detect the degree of impairment, particularly by health-care providers working outside of the hospital.