Self-perceived quality of sleep and mortality in Norwegian dialysis patients

Sleep complaints are prevalent and associated with poor health-related quality of life (HRQoL), depression and possibly mortality in dialysis patients. This study aimed to explore possible associations between sleep quality, daytime sleepiness and mortality in dialysis patients. In this study, 301 dialysis patients were followed up to 4.3 years. HRQoL was evaluated at baseline with the Kidney Disease and Quality of Life--Short Form (KDQoL-SF), depression with Beck Depression Inventory (BDI), sleep quality with Pittsburgh Sleep Quality Index and daytime sleepiness with Epworth Sleepiness Scale. The single item "on a scale from 0-10, how would you evaluate your sleep?" in the sleep subscale in KDQoL-SF was used to identify poor (0-5) and good sleepers (6-10). A total of 160 patients (53.3%) were characterized as poor sleepers. They were younger (r = 0.241, P < 0.001), had more depression (BDI: 8.72 ± 6.79 vs. 13.60 ± 8.04, P < 0.001), a higher consumption of hypnotics and antidepressants and reduced HRQoL (Mental Component Summary score: 45.4 ± 11.0 vs. 50.0 ± 10.4, P < 0.001. Physical Component Summary score: 35.0 ± 9.9 vs. 38.5 ± 10.5, P = 0.004). In multivariate analyses, poor sleepers had nearly a twofold increase in mortality risk (hazard ratio [HR] 1.92, confidence interval [CI] 1.10-3.35, P = 0.022). Daytime sleepiness was not related to mortality (HR 1.01, CI 0.95-1.08, P = 0.751). Sleep complaints predicted increased mortality risk in dialysis patients and should therefore be routinely assessed. Further studies are needed to find suitable treatment options for poor sleep in dialysis patients as it may affect both HRQoL and survival.