Dialysis-Imposed Patterns of Nocturnal Sleep Duration: A Multi-Center Prospective Study in Patients Using a Wearable Activity Tracker

BACKGROUND: In patients on hemodialysis, the effects of determinants of sleep duration are not widely studied. Using wearable activity trackers, we aimed to characterize natural and hemodialysis-imposed temporal patterns of nocturnal sleep. METHODS: In this yearlong prospective observational study, patients on in-center hemodialysis were equipped with activity trackers (Fitbit® Charge 2™). Nocturnal sleep duration was assessed according to dialysis start time (early starters: before 8 a.m., late starters: others), dialysis versus interdialytic days (post-dialysis day and 2nd interdialytic day), weekdays, and seasons. Clinical, laboratory, and hemodialysis treatment data were extracted from electronic medical records. Linear mixed-effects models were constructed to determine the effect of various time patterns and predictors of nocturnal sleep duration. RESULTS: 109 patients contributed data (age 54±12 years, 73% males, 23% diabetic). Sleep duration was 276±91 minutes; 102 (94%) patients slept on average less than the recommended 420 minutes per night. On dialysis days, participants slept 55 (95% CI [51,59]) and 48 (95% CI [43,54]) minutes less compared to post-dialysis and 2nd interdialytic days, respectively. Early starters slept on average 40 (95% CI [6,74]) minutes less compared to late starters. On dialysis days, early starters slept 86 (95% CI [55,118]) minutes less compared to late starters. We observed greater sleep-wake disturbance in early starters. Irrespective of dialysis schedule, patients slept on average 26 (95% CI [19,33]) to 32 (95% CI [24,40]) minutes longer on Sunday. In winter, sleep was 7 (95% CI [1,13]) to 10 (95% CI [5,16]) minutes shorter. In multivariate analysis, higher blood pressure and higher serum creatinine were significantly associated with shorter sleep duration. CONCLUSIONS: On average, patients on hemodialysis slept less than the recommended amount of time. The timing of hemodialysis treatment has pronounced effects on sleep duration and could be considered in patient care.