Supplementary Material for: Effect of Nocturnal Haemodialysis on Body Composition

Background: Haemodialysis patients have a high risk of malnutrition which is associated with increased mortality. Nocturnal haemodialysis (NHD) is associated with a significant increase in protein intake compared with conventional haemodialysis (CHD). It is unclear whether this leads to improved nutritional status. Therefore, we studied whether 1 year of NHD is associated with a change in body composition. Methods: Whole-body composition using dual-energy X-ray absorptiometry (DEXA) and normalised protein catabolic rate (nPCR) were measured in 11 adult patients before and 1 year after the transition from CHD (12 h dialysis/week) to NHD (28-48 h dialysis/week). Similar measurements were performed in a matched control group of 13 patients who stayed on CHD. Differences between groups were analysed with linear mixed models. Results: At baseline, nPCR, total mass, fat-free mass, and fat mass did not differ significantly between the CHD and NHD groups. nPCR increased in the NHD group (from 0.96 ± 0.23 to 1.12 ± 0.20 g/kg/day; p = 0.027) whereas it was stable in the CHD group (0.93 ± 0.21 at baseline and 0.87 ± 0.09 g/kg/day at 1 year, n.s.). The change in nPCR differed significantly between the two groups (p = 0.027). We observed no significant differences in the course of total mass, fat-free mass, and fat mass during the 1-year observation period between the NHD and CHD groups. Conclusions: One year of NHD had no significant effect on body composition in comparison with CHD, despite a significantly higher protein intake in patients on NHD.