Antagonistic implications of sarcopenia and abdominal obesity on physical performance in COPD

Decreased physical performance due to loss of muscle mass (i.e. sarcopenia) is prevalent in ageing and appears more pronounced in chronic disease. A comprehensive profile of the sarcopenic phenotype in chronic obstructive pulmonary disease (COPD) is not yet available. The aim of the present study was to characterise prevalence, functional implications and predictive value of sarcopenia with or without abdominal obesity in Dutch COPD patients eligible for pulmonary rehabilitation. 505 COPD patients (aged 37-87 years; 57% male) underwent assessment of lung function, body composition and physical functioning, before entering pulmonary rehabilitation. Sarcopenia was assessed by appendicular skeletal muscle index (ASMI) and abdominal obesity by android/gynoid percentage fat mass (A/G%FM) using dual energy X-ray absorptiometry (DEXA). 86.5% of patients were sarcopenic and showed lower physical functioning, while coexistent abdominal obesity (78.0%) resulted in higher physical functioning. Implications on endurance were less pronounced in women. The predictive value for physical functioning was higher for the "three-compartment" model (ASMI, bone mineral content and A/G%FM) than the "two-compartment" model (fat-free mass index and fat mass index) or "one-compartment" model (body mass index). In patients eligible for pulmonary rehabilitation, sarcopenia is highly prevalent in all BMI-categories and associated with impaired strength, and in men also with decreased endurance. Abdominal obesity seems to have protective effects on physical functioning. ASMI is a better predictor for physical functioning than FFMI.