Different melatonin rhythms and sleep-wake rhythms in patients on peritoneal dialysis, daytime hemodialysis and nocturnal hemodialysis

Background: Little comparative data on sleep-wake rhythms in different dialysis groups exist. The aim of this study was to investigate sleep-wake parameters measured with actigraphy and sleep questionnaires as well as melatonin rhythms in automated peritoneal dialysis, conventional daytime hemodialysis and nocturnal hemodialysis patients.
Methods: Conventional daytime dialysis (n = 20), nocturnal hemodialysis (n = 13) and automated peritoneal dialysis patients (n = 6) were included in the study. Melatonin in saliva was sampled at 5 time points (21:00, 23:00, 1:00, 7:00 and 9:00 h). Furthermore, actigraphy measurements and sleep questionnaires were performed. All parameters were tested by Kruskall-Wallis test (followed by post hoc Dunn test) to find significant differences (p < 0.05).
Results: Although most sleep parameters were impaired in all three groups, conventional daytime dialysis patients had the worst sleep. In nocturnal hemodialysis patients a normal nocturnal melatonin rise was found. In daytime hemodialysis and automated peritoneal dialysis patients this rise was absent.
Conclusions: The study showed impaired sleep parameters in all dialysis patient groups. As automated peritoneal dialysis is also performed during night time, the same effect on normalized melatonin was anticipated as was found in nocturnal hemodialysis. Melatonin seems to play a subordinate role in the sleep-wake rhythm of automated peritoneal dialysis patients.