Long-term body composition changes in patients undergoing hemodialysis: a single-center retrospective study

Background Patients undergoing dialysis experience substantial decreases in muscle mass and functional muscle weakness. Muscle mass loss in patients undergoing hemodialysis is an independent predictor of survival, so muscle mass maintenance is essential for continued hemodialysis. This study examined longitudinal changes in the body composition of patients undergoing hemodialysis in different dialysis periods. Methods We retrospectively analyzed body composition measurements obtained by bioelectrical impedance analysis (BIA) using the same measuring instrument. The dialysis periods were 1-10 years from the start of hemodialysis for group A (n = 25), 10-20 years for group B (n = 22), and 20-30 years for group C (n = 9). The initial and final measurements of each group were compared. Furthermore, the nutritional status based on the inflammation and nutritional indicators obtained during the measurement period of each group was examined. Results Muscle mass did not significantly decrease in groups A and B but did decrease in group C (P < 0.05). In all groups, the extracellular water-to-total body water ratio (ECW/TBW) significantly increased (P < 0.001). C-reactive protein in groups A and B increased; however, the median initial and final values were < 0.2 mg/dL, and no changes were observed in group C. Furthermore, the median normalized protein catabolic rate was 0.86-1.05 g/kg/day, and there was no difference in the initial or final rates. The mean energy and protein daily intakes were 30-32 kcal/ideal body weight (IBW) kg/day and 1.1 g/IBW kg/day, respectively. Conclusions In patients undergoing hemodialysis, even if the muscle mass values are maintained, the possibility of a substantial decrease in muscle mass cannot be ruled out when ECW/TBW increases. Control of inflammation and nutritional intake may help minimize muscle mass loss caused by continued hemodialysis in patients.