Effect of predialysis fluid overload on sleep quality in hemodialysis patients

Abstract

Background Sleep disorders are common among end-stage renal disease patients undergoing hemodialysis (HD). The etiology of sleep disorders in these patients is known to be multifactorial. However, the role of hydration status in sleep disorders in HD patients is not well studied. Therefore, our aim was to study the effect of predialysis fluid overload on sleep quality in HD patients. Patients and methods This cross-sectional study included 100 prevalent HD patients from the HD unit of El Sahel Teaching Hospital. Fluid status and fluid compartments [total body water), extracellular water (ECW),and overhydration (OH) index] were analyzed by a portable whole-body bioimpedance spectroscopy (body composition monitor) before a mid-week dialysis session. OH was defined as OH/ECW% more than or equal to 15%. HD patients were then classified into two groups: group 1 (normohydrated) and group 2 (overhydrated) according to the relative OH index (OH/ECW%). Sleep quality was assessed in all patients by the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Patients with concurrent diagnosis of either obstructive sleep apnea or psychiatric disorder and patients on any medications that affect the sleep pattern were excluded. Results Our study included 100 HD patients (49 male, 51 female; mean age, 49.3 ± 11); 42 (42%) patients had OH (i.e. group 2). Poor sleep quality (defined as PSQI score ≥5) was reported in 57% (n=57) of HD patients included in our study. Poor sleep quality was significantly higher in the HD patients with OH (group 2). Total PSQI scores were significantly higher in overhydrated patients (group 2) compared with normohydrated patients (group 1) (7.92 ± 3.32 vs. 4.83 ± 2.27, P≤0.001). The component scores 1, 2, 3, 4, 6, and 7 of the PSQI showed significant higher values (i.e. poor sleep quality) in overhydrated patients (group 2). Moreover, there was significant positive correlation between total PSQI score both of OH (r=0.259, P=0.009) and OH index (OH/ECW%) (r=0.283, P=0.004) in all HD patients included in the study. Conclusion We may conclude from our study that sleep disorders are prevalent in HD patients. Predialysis fluid overload in HD patients may be associated significantly with poor sleep quality.