Association of sleep disturbances with cognitive impairment and depression in maintenance hemodialysis patients

Background: There are few data on the relationship of sleep with measures of cognitive function and symptoms of depression in dialysis patients. Methods: We evaluated the relationship of sleep with cognitive function and symptoms of depression in 168 hemodialysis patients, using multivariable linear and logistic regression. Sleep disturbances were assessed using the sleep subscale battery of the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) Health Experience Questionnaire. The cognitive battery assessed a broad range of functioning including global ability, verbal intelligence, supraspan learning, auditory retention, visual retention, attention/mental processing speed, visual construction/fluid reasoning and motor speed. Depressive symptoms were assessed using the Center for Epidemiological Studies of Depression (CESD) Scale, with depression indicated by a CESD score >= 16. Results: Mean (SD) age of participants was 62 (17) years, 49% were women, 30% were African American and 33% had diabetes. There was no significant relationship between sleep score and performance on any neurocognitive test (p>0.13, for all multivariable analyses). The prevalence of depression increased from 16% in the highest quartile (best) of sleep score, to 31% in the lowest quartile (worst) of sleep score. In multivariable analyses, each 1 SD increase in sleep score was associated with a 2.18 (95% confidence interval, 1.07-3.29, p<0.001) lower CESD score. Results were consistent when considering individual components of both the CESD and sleep score. Conclusions: Disturbances in sleep are associated with symptoms of depression but not measures of cognitive function. Dialysis patients with disturbances in sleep should be screened for depression.