The aim of this study was to investigate the effects of exogenous melatonin on sleep-wake rhythm in haemodialysis patients.
The study design is a randomized, double-blind, placebo-controlled, cross-over study of 3 x 6 weeks melatonin 3 mg at 22.00 h every night. Haemodialysis patients were asked to fill out a sleep questionnaire and to wear an actometer to record their sleep problems objectively. Furthermore, melatonin concentrations in saliva were sampled the night after daytime haemodialysis and the consecutive night. Actometers, the sleep questionnaire and melatonin concentrations were repeated during the study.
In total, 20 patients (six female, median age 71 years) completed the investigation. On nights after daytime dialysis, objective sleep onset latency decreased significantly from a median of 44.5 (placebo) to a median of 15.5 min with melatonin (P < 0.01). Sleep efficiency increased from 67.3 to 73.1% with melatonin (P < 0.05). Actual sleep time increased from 376 min (placebo) to 388 min with melatonin (P < 0.01), and sleep fragmentation decreased from 4.5 to 3.1 (P < 0.01). Furthermore, subjective sleep parameters improved also. Patients reported less time needed to fall asleep (P < 0.05) and fewer wake periods (P < 0.05) on the nights with and without daytime dialysis and an increase in sleep time on the night of daytime dialysis (P < 0.05). Furthermore, the nocturnal melatonin rise was recovered.
Treatment with melatonin resulted in an improvement of subjective and objective sleep parameters, as well as a recovered nocturnal melatonin rhythm.