Body Composition Changes in Hospitalized Patients with Community-Acquired Pneumonia

<b>Background</b>: The influence of hospitalization owing to pneumonia on changes in body composition has not been specifically reported. We conducted a prospective cohort study of patients with community-acquired pneumonia (CAP) requiring hospitalization to test the hypothesis that hospitalization affects body composition. <b>Methods</b>: Sixty-four consecutive patients with CAP were recruited. Body composition was measured within 24 h of admission and 24 h before discharge using bioelectrical impedance analysis. The association between changes in body composition and variables obtained at admission was investigated. Index values were calculated as weight divided by height squared. <b>Results</b>: The mean age of the patients was 76.0 ± 8.7 years (78.1% males). The median length of hospitalization was 12.0 days. Weight, body mass index (BMI), skeletal muscle (SM), SM index, fat-free mass (FFM), and FFM index significantly decreased (<i>p</i> < 0.001 for each), but fat mass (FM) and FM index did not. The serum total protein level was the only independent predictor of the lowest quartile of change in SM index (<-0.4) after adjusting for age and sex (<i>p</i> = 0.004). <b>Conclusions</b>: In summary, weight and BMI significantly decreased during hospitalization in patients with CAP, which was attributed to SM reduction. Patients with low serum total protein levels on admission were at risk of an accelerated decrease in the SM index. Nutritional intervention and rehabilitation are important for these patients.