Effects of six versus three times per week hemodialysis on physical performance, health, and functioning: Frequent hemodialysis network (FHN) randomized trials

Background and objectives Relatively little is known about the effects of hemodialysis frequency on the disability of patients with ESRD. Design, setting, participants, & measurements This study examined changes in physical performance and selfreported physical health and functioning among subjects randomized to frequent (six times perweek) compared with conventional (three times per week) hemodialysis in both the Frequent Hemodialysis Network daily (n=245) and nocturnal (n=87) trials. The main outcome measures were adjusted change in scores over 12 months on the short physical performance battery (SPPB), RAND 36-item health survey physical health composite (PHC), and physical functioning subscale (PF) based on the intention to treat principle. Results Overall scores for SPPB, PHC, and PF were poor relative to population norms and in line with other studies in ESRD. In the Daily Trial, subjects randomized to frequent compared with conventional in-center hemodialysis experienced no significant change in SPPB (adjusted mean change of 20.2060.19 versus 20.4160.21, P=0.45) but experienced significant improvement in PHC (3.460.8 versus 0.460.8, P=0.009) and a relatively large change in PF that did not reach statistical significance. In the Nocturnal Trial, there were no significant differences among subjects randomized to frequent compared with conventional hemodialysis in SPPB (adjusted mean change of 20.9260.44 versus 20.4160.43, P=0.41), PHC (2.761.4 versus 2.161.5, P=0.75), or PF (23.163.5 versus 1.163.6, P=0.40). Conclusions Frequent in-center hemodialysis compared with conventional in-center hemodialysis improved self-reported physical health and functioning but had no significant effect on objective physical performance. There were no significant effects of frequent nocturnal hemodialysis on the same physical metrics.