Nutritional Status of Patients with Chronic Obstructive Pulmonary Disease in Relation to their Physical Performance

Nutritional abnormalities and physical inactivity are highly prevalent in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to determine the association between nutritional status/body composition and physical performance in patients with COPD. A cross-sectional observational study was conducted in outpatients with clinically stable, moderate to very severe COPD. In the assessment of nutritional status, we used dual energy X-ray absorptiometry, anthropometry, serum biomarkers, and the Mini-Nutritional Assessment (MNA) questionnaire. Physical performance was measured by the 6-minute walk distance (6MWD), 4-metre gait speed (4MGS), and physical activity. Univariate and multivariate analyses were performed. In 111 patients (mean age 68 years, 69% men), the mean 6MWD was 376 +/- 119m, 4MGS 0.9 +/- 0.2m/s, and the average daily step count 8,059 +/- 4,757. Patients with low exercise capacity (6MWD 350 m) had a significantly lower lean mass index (LMI) (p < 0.01), fat-free mass index (FFMI) (p < 0.01), bone mineral content (p < 0.01), bone mineral density (p < 0.01), T-score (p < 0.05), MNA score (p < 0.01), and serum albumin and prealbumin levels (p < 0.05). Patients with low physical activity (daily step count median) had lower LMI, FFMI, MNA score, serum prealbumin (for all comparisons p < 0.05) and vitamin D levels (p < 0.01). However, none of the nutritional variables showed an independent association with low physical performance in the multivariate models. In conclusion, patients with low physical performance have deficient nutritional status, but we could not demonstrate an independent relationship between nutritional parameters and physical performance.