Lower FFMI in female compared to male patients with COPD admitted to pulmonary rehabilitation

Background: Patients with chronic obstructive pulmonary disease (COPD) often struggle to maintain body weight. It is recognized that a body mass index (BMI) < 21 kg/m2 has adverse effects on health status in COPD. Loss of fat free mass (FFM) is common, and is negatively associtated with exercise capacity, quality of life and survival. Depletion in FFM has been suggested as fat free mass index (FFMI) < 16 kg/m2 for men and <15 kg/m2 for women, and has been found to be an independent and better predictor of survival than BMI. Aim: The study aimed to evaluate if screening of body composition in COPD patients is valuable in order to detect muscle wasting. Methods: COPD-patients on an in-patient four-week rehabilitation program were consecutively included. Lung function and body composition tests were performed according to the standardized procedures. Results : 274 COPD patients (43% men) were included. Mean (SD) age 64 (9) yrs, FEV1% pred 47 (18) %. BMI (kg/m2) was 26.3 (6.2) and 25.8 (6.0) for men and women, respectively (p=0.858). FFMI (kg/m2) was 18.9 (3.0) for men and 15.8 (1.9) for women (p<0.001). 20 (17%) of all men, and 52 (33%) (p=0.002) of all women had FFMI below recommended limit; low FFMI was more frequent in those with low BMI and GOLD 4. A low FFMI was found in 26% of the men and 64% of the women with normal BMI. Conclusion: The prevalence of low FFMI among COPD patients admitted to rehabilitation is similar to previous studies. However, female patients have a significantly higher risk of depletion in FFM compared to men.