Predialysis volume overload and patient-reported sleep duration and quality in patients receiving hemodialysis

Introduction: Previous studies of patients with end-stage renal disease have examined the role of fluid shifts on apnea-hypopnea episodes, but the association between volume overload and patient-reported sleep quality or duration has not been well-established.

Methods: We studied the association between predialysis bioimpedance spectroscopy-derived volume estimates and self-reported sleep quality and duration in 638 patients in the United States Renal Data System ACTIVE/ADIPOSE study receiving hemodialysis from 2009 to 2011. We used questionnaires to assess self-reported sleep duration and quality. We used relative hydration status (fluid overload/extracellular water; FO/ECW) as the primary predictor and examined associations with hours of sleep duration using linear regression. We used multivariable ordinal logistic regression to determine the association between categories of relative hydration status (normal hydration [FO/ECW < 6.8%], mild overhydration [FO/ECW 6.8%-15%], and hyperhydration [FO/ECW > 15%]) and four levels of difficulty with falling asleep, waking, and returning to sleep.

Findings: Higher relative hydration status was associated with fewer hours of sleep (-0.31 hours per 10%, 95% confidence interval (CI) -0.49 to -0.13). Compared to the normal hydration group, there was a statistically significant association between higher relative hydration status category and more frequent nighttime waking (OR: mild overhydration 1.92 [95% CI 1.23-2.99], hyperhydration 1.87 [95% CI 1.16-2.99]), a trend toward more difficulty returning to sleep (OR: mild overhydration 1.46 [95% CI 0.94-2.27], hyperhydration 1.52 [95% CI 0.95-2.43]), and no association between relative hydration category and difficulty falling asleep.

Discussion: Hydration status was associated with self-reported sleep duration in patients on dialysis. Future studies should prospectively examine the effects of optimizing fluid status on sleep duration and quality.