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 AM; late starters: others), dialysis versus interdialytic days (postdialysis day and second 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 One hundred nine patients contributed data (age 54612 years, 73% male, 23% diabetic). Sleep duration was 276691 minutes; 102 (94%) patients slept on average less than the recommended 420 minutes per night. On dialysis days, participants slept 55 (95% confidence interval [CI], 51 to 59) and 48 (95% CI, 43 to 54) minutes less compared with postdialysis and second interdialytic days, respectively. Early starters slept on average 40 (95% CI, 6 to 74) minutes less compared with late starters. On dialysis days, early starters slept 86 (95% CI, 55 to 118) minutes less compared with late starters. We observed greater sleep–wake disturbance in early starters. Irrespective of dialysis schedule, patients slept on average 26 (95% CI, 19 to 33) to 32 (95% CI, 24 to 40) minutes longer on Sundays. In winter, sleep was 7 (95% CI, 1 to 13) to 10 (95% CI, 5 to 16) minutes shorter. In multivariate analysis, higher BP 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.