Predictors of poor sleep quality and excessive daytime sleepiness in peritoneal dialysis patients

To explore the possible impact factors on daytime sleepiness among peritoneal patients from a single center in China. A cross-sectional study was conducted in 98 prevalent peritoneal dialysis (PD) patients using both the Pittsburgh Sleep Quality Index (PSQI) questionnaire of sleep quality and the Epworth Sleepiness Scale (ESS) questionnaire of excessive daytime sleepiness (EDS). Biochemical differences between daytime sleepiness and non-daytime sleepiness population were evaluated, following univariate and multivariable analysis to find the risk factors on sleep disturbance. The prevalence of "poor sleep quality'' (PSQI>5) was 74.49%, while daytime sleepiness (ESS >= 9) occurred in 22.45%. Mean PSQI was 9.06 +/- 4.60 and EES was 6.31 +/- 4.98. Compared to non-EDS cases, patients with ESS >= 9 had worse residual renal function (RRF), higher serum creatinine, higher serum magnesium and elevated serum ferritin. In univariate analysis, ESS correlated with serum albumin (r = 0.346, p = 0.015), phosphate (r = 0.313, p = 0.029), magnesium (r = 0.376, p = 0.008) and urinary Kt/V (r = -0.341, p = 0.029). Finally, multivariable linear regression indicated that urinary Kt/V, PSQI and magnesium were independent predictors of ESS score. EDS does exist in PD patients and is associated both with poor nighttime sleep quality and lower RRF. Hypermagnesemia may be a treatable risk factor to improve daytime tiredness.