Body composition and physical activity in end-stage renal disease.

OBJECTIVE The study objective was to examine the relationship between visceral and somatic protein stores and physical activity in individuals with end-stage renal disease. DESIGN This was a prospective single-center study. SETTING The study took place at the Vanderbilt University Outpatient Dialysis Unit and General Clinical Research Center. PATIENTS Fifty-five patients with prevalent chronic hemodialysis (CHD) were included: 33 males, 22 females, 45 African Americans, 9 Caucasians, and 1 Asian. The mean age was 47.0 +/- 1.6 years, height was 166.4 +/- 13.9 cm, and weight was 83.1 +/- 2.6 kg. METHODS Body composition was measured by dual-energy x-ray absorptiometry. Minute-by-minute physical activity was assessed over a 7-day period with a triaxial accelerometer. Participants were interviewed by a trained registered dietitian for two 24-hour diet recalls (one from a hemodialysis day; one from a nonhemodialysis day). Laboratory values for serum concentrations of albumin, prealbumin, C-reactive protein, and creatinine were also collected. MAIN OUTCOME MEASURE Predictors of somatic protein stores were the main outcome measure. RESULTS Serum albumin was negatively and significantly correlated with the percentage of fat mass (P = .016) and kg of fat mass (P = .044). C-reactive protein was positively and significantly correlated with body weight (P = .006), percentage of fat mass (P = .017), kg of fat mass (P = .006), and body mass index (P = .004). Physical activity and total daily protein intake were the strongest predictors of the amount of lean body mass (P = .01 and .003, respectively). CONCLUSION The association between somatic protein and visceral protein stores is weak in patients with CHD. Whereas increased levels of physical activity and total daily protein intake are associated with higher lean body mass in patients with CHD, higher adiposity is associated with higher C-reactive protein and lower albumin values.