The relationship between fat-free mass index and pulmonary hyperinflation in COPD patients.

BACKGROUND AND OBJECTIVE: Reduced fat-free mass (FFM), a common finding in chronic obstructive pulmonary disease (COPD), may indirectly impact peak exercise capacity through a greater level of pulmonary hyperinflation. We aimed to investigate if FFM index (FFM/squared height) impacts exercise induced dynamic hyperinflation in COPD patients. METHODS: Fifty-four patients with moderate-to-very severe COPD performed a symptom limited incremental cardiopulmonary exercise tests with serial measurements of inspiratory capacity (IC). FFM was measured by whole-body bioelectrical impedance. RESULTS: Patients were 66.7 ± 7.7 years old with mean forced expiratory volume in 1 s (FEV1) of 1.08 ± 0.41 L (42 ± 15% of predicted). Peak exercise IC was significantly (P < 0.05) correlated with IC at rest (r = 0.78), FEV1(r = 0.66), FVC (r = 0.59), FFM (r = 0.38) and FFM index (r = 0.29). However, only FEV1 and rest IC predict peak IC (r = 0.86; P < 0.01) in a multivariate linear regression analysis. CONCLUSIONS: FFM index was weakly associated with peak exercise IC in COPD patients. However, it ceased to be an independent predictor when corrected for expiratory airflow limitation (FEV1) and lung hyperinflation at rest (rest IC).

Effectiveness of pulmonary rehabilitation in exercise capacity and quality of life in chronic obstructive pulmonary disease patients with and without global fat-free mass depletion.

OBJECTIVE: To investigate the effectiveness of pulmonary rehabilitation (PR) in exercise capacity and quality of life in patients with chronic obstructive pulmonary disease (COPD) with and without global fat-free mass (FFM) depletion. DESIGN: Retrospective case-control. SETTING: Outpatient clinic, university center. PARTICIPANTS: COPD patients (N=102) that completed PR were initially evaluated. INTERVENTION: PR including whole-body and weight training for 12 weeks, 3 times per week. MAIN OUTCOME MEASURES: St. George Respiratory Questionnaire (SGRQ), 6-minute walk distance (6MWD), and FFM evaluation applied before and after PR. RESULTS: Patients were stratified according to their FFM status measured by bioelectric impedance. They were considered depleted if the FFM index was ≤ 15 kg/m(2) in women and ≤ 16 kg/m(2) in men. From the initial sample, all depleted patients (n=31) composed the FFM depleted group. It was composed predominantly by women (68%) with a mean age ± SD of 64.4 ± 7.3 years and a forced expiratory volume in 1 second of 33.6%=-13.2% predicted. Paired for sex and age, 31 nondepleted patients were selected from the initial sample to compose the nondepleted group. Improvement in the 6MWD was similar in these 2 groups after PR. Both groups improved SGRQ scores, although the observed power was small and did not allow adequate comparison between depleted and nondepleted patients. There was no difference between groups in weight change, whereas FFM tended to be greater in depleted patients. This increase had no correlation with the 6MWD or the SGRQ. CONCLUSIONS: Benefits of PR to exercise capacity were similar comparing FFM depleted and nondepleted COPD patients. Although FFM change tended to be greater in depleted patients, this increase had no definite relation with clinical outcomes.