Skeletal muscle is associated with exercise tolerance evaluated by cardiopulmonary exercise testing in Japanese patients with chronic obstructive pulmonary disease

Abstract

Abstract Decreasing exercise tolerance is one of the key features related to a poor prognosis in patients with chronic obstructive pulmonary disease (COPD). Cardiopulmonary exercise testing (CPET) is useful for evaluating exercise tolerance. The present study was performed to clarify the correlation between exercise tolerance and clinical parameters, focusing especially on the cross-sectional area (CSA) of skeletal muscle. The present study investigated 69 patients with COPD who underwent CPET. The correlations between oxygen uptake ( $${{\dot{\text{V}} \text{O}}}_{2}$$ V ˙ O 2 ) at peak exercise and clinical parameters of COPD, including skeletal muscle area measured using single-section axial computed tomography (CT), were evaluated. The COPD assessment test score (ρ = − 0.35, p = 0.02) was weakly correlated with $${{\dot{\text{V}} \text{O}}}_{2}$$ V ˙ O 2 at peak exercise. In addition, forced expiratory volume in one second (FEV1) (ρ = 0.39, p = 0.0009), FEV1/forced vital capacity (ρ = 0.33, p = 0.006), and the CSA of the pectoralis muscles (PMs) (ρ = 0.36, p = 0.007) and erector spinae muscles (ECMs) (ρ = 0.39, p = 0.003) were correlated with $${{\dot{\text{V}} \text{O}}}_{2}$$ V ˙ O 2 at peak exercise. Multivariate analysis adjusted by age and FEV1 indicated that PMCSA was weakly correlated after adjustment (β value [95% confidence interval] 0.175 [0.03–0.319], p = 0.02). In addition, ECMCSA tended to be correlated, but not significantly after adjustment (0.192 [− 0.001–0.385] p = 0.052). The COPD assessment test, FEV1, FEV1/FVC, PMCSA, and ECMCSA were significantly correlated with $${{\dot{\text{V}} \text{O}}}_{2}$$ V ˙ O 2 at peak exercise.