Sleep complaints, depression and quality of life in Norwegian dialysis patients

Background: This study explores sleep problems in dialysis patients and the associations to health-related quality of life (HRQoL) and depression. A comparison between different validated sleep questionnaires was done in order to find an appropriate diagnostic tool in clinical practice. Methods: In a cross-sectional study of 301 prevalent dialysis patients, sleep problems were elaborated with Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Poor sleep was defined as PSQI score > 5 and daytime sleepiness as ESS > 10. HRQoL, including quality of sleep, was evaluated with the Kidney Disease and Quality of Life - Short Form (KDQoL-SF), and physical (PCS) and mental component summary scores (MCS) were computed. Depression was assessed with Beck Depression Inventory (BDI). Results: Poor sleep and excessive daytime sleepiness was found in 74.3% and 22.2%, respectively. Depression was common (29.5%) and associated with reduced sleep quality (rho = 0.49, p < 0.001). Poor sleepers had significantly lower MCS (51.8 +/- 9.6 vs. 46.6 +/- 10.6, p = 0.001) and PCS (41.8 +/- 9.6 vs. 35.2 +/- 10.0, p < 0.001) compared to good sleepers. PSQI scores were independently associated with PCS (p = 0.001), but not MCS (p = 0.468) in multivariate analyses. The sleep subscale from KDQoL-SF was strongly correlated to PSQI (r = -0.75, p < 0.001). Conclusions: As sleep complaints, daytime sleepiness and depression were prevalent, all dialysis patients should routinely be screened for self-perceived sleep problems with a simple questionnaire.