OBJECTIVE: The present study focuses on the prevalence of nutritional depletion in relation to functional performance, airflow limitation, experienced dyspnoea and health status in a large multi-center out-patient population with chronic obstructive pulmonary disease (COPD). METHODS: In 39 out-patient centers in The Netherlands, 389 patients with moderate to severe COPD (217 men) were recruited. The study evaluated on the baseline characteristics of the COSMIC study. Measurements included body composition by bioelectrical impedance analysis, dyspnoea by MRC-score, peripheral muscle function by isometric handgrip strength and disease-specific health status by St. George Respiratory Questionnaire. RESULTS: The prevalence of nutritional depletion (defined as body mass index (BMI)<or=21 kg/m2 and/or fat-free mass index (FFMI)<or=15 (females) or <or=16 (males) kg/m2) was high (27%). Prevalence of normal BMI and low FFMI was 15%, and of low BMI and low FFMI 11%. The prevalence of low BMI as well as low FFMI was significantly higher in female than in male COPD patients, 18% and 40% vs. 10% and 20%, respectively (both P<0.01). No differences in FEV1%predicted, dyspnoea score and health status were observed between depleted and non-depleted COPD patients. Multiple linear regression analysis in the total group showed that handgrip strength correlated with FFMI after correction for sex distribution and age, but not FEV1%predicted. CONCLUSIONS: The prevalence of nutritional depletion was high in a large out-patient COPD population in The Netherlands, especially in female COPD patients. Depletion of FFM was associated with impaired peripheral muscle strength, independent of disease severity.