[Correlation of body composition indicators with exercise capacity and nutritional status in male patients with chronic obstructive pulmonary disease].

Objective: To investigate the correlation of body composition indices with exercise capacity and nutritional status in male chronic obstructive pulmonary disease (COPD) patients. Methods: The clinical data of 90 male COPD patients admitted to the Department of Respiratory and Critical Care Medicine of China-Japan Friendship Hospital from January 2021 to September 2022 were retrospectively collected, and the patients were subjected to a pulmonary function test, body composition measurement, 6-minute walking test distance (6MWD) test, and dominant handgrip strength measurement (HGS). The patients were categorized into COPD Global Initiative for COPD (GOLD) grade 1, 2, 3 and 4 groups according to the severity of lung function. Based on the fat-free mass index (FFMI), patients were categorized into a low FFMI group (FFMI<17 kg/m²) and a normal FFMI group (FFMI≥17 kg/m²). Based on phase angle (PhA), patients were categorized into the low PhA group (PhA<5°) and the normal PhA group (PhA≥5°). Based on 6MWD, patients were divided into impaired endurance group (6MWD<350 m) and normal endurance group (6MWD≥350 m). Differences in body composition indexes, exercise capacity, and nutritional status of patients in different subgroups were compared. A trend test was used to analyze the trend of GOLD grading and body composition indexes. Correlation analysis was used to analyze the correlation of FFMI, PhA, skeletal muscle mass index (SMI), basal metabolic rate (BMR), and visceral fat index (VFI) with 6MWD, HGS, post-diastolic exertional expiratory volume in the first second as a percentage of exertional lung capacity (FEV₁%pred), and body mass index (BMI). Results: The age of 90 male COPD patients was 66 (59, 71) years. FFMI, PhA, SMI, BMR, VFI, HGS, and 6MWD tended to decrease with increasing GOLD levels (all P<0.05). In the low FFMI group (31 cases), PhA [5.0° (4.7°, 5.1°) vs 5.8° (5.6°, 6.3°)], SMI [6.3 (5.3, 6.9)vs 8.3 (7.7, 9.1) kg/m²], and BMR [(1 294.5±387.2) vs (1 538.7±207.5) kcal(1 kcal=4.184 kJ)], VFI [(10.0±4.2) grades vs (14.2±3.3) grades], 6MWD [(430.5±90.8) vs (537.2±85.5) m], FEV₁%pred [(37.8±7.9)% vs (73.7±21.5)%], BMI [(20.2±3.8) vs (25.5±2.9) kg/m²] were lower than those in the normal FFMI group (59 cases, all P<0.05). In the low PhA group (23 cases), FFMI [(16.7±2.2) vs (19.5±1.5) kg/m²], SMI [6.6 (5.9, 7.0) vs 7.3 (7.7, 9.0) kg/m²], BMR [(1 251.8±246.2) vs (1 547.5±206.6) kcal], 6MWD [(451.0±47.1) vs (538.3±87.5) m], HGS [(29.6±4.0) vs (36.4±7.2) kg], FEV₁%pred [(51.2±15.3)% vs (72.9±22.8)%], BMI [(20.9±3.7) vs (25.5±2.8) kg/m²] were lower than those of the normal PhA group (67 cases, all P<0.05). In the impaired endurance group (21 cases) PhA [5.2° (5.1°, 5.3°) vs 5.8° (5.6°, 6.3°)], FEV₁%pred [(34.2±15.4)% vs (72.7±22.2)%] were lower than those in the normal endurance group (69 cases, all P<0.05). Correlation analysis showed that FFMI was positively correlated with HGS, FEV₁%pred, and BMI (r values of 0.327, 0.235, and 0.782, all P<0.05); PhA was positively correlated with 6MWD, FEV₁%pred, and BMI (r values of 0.341, 0.258, and 0.251, all P<0.05); SMI was positively correlated with HGS and BMI (r values of 0.411 and 0.710, all P<0.05); BMR was positively correlated with 6MWD, HGS, FEV₁%pred, and BMI (r values of 0.338, 0.508, 0.285, and 0.676, all P<0.05); VFI was positively correlated with BMI (r value of 0.791, P<0.001). Conclusions: FFMI is positively correlated with HGS, FEV₁%pred, and BMI; PhA is positively correlated with 6MWD, FEV₁%pred, and BMI; SMI is positively correlated with HGS and BMI; BMR is positively correlated with 6MWD, HGS, FEV₁%pred, and BMI; VFI is positively correlated with BMI. Body composition indexes may reflect the exercise capacity and nutritional status of male COPD patients.