Patient-reported sleep difficulty and cognitive function during the first year of dialysis

Background Research in the general population indicates that sleep fragmentation is detrimental for cognitive function, but little attention has been given to this issue in dialysis patients. We hypothesized that patients with self-reported persistent sleep difficulty would have an increased risk of scoring lower on a cognitive function measure at follow-up compared to their score at baseline. Methods Sleep difficulty and cognitive function were reported by a large national patient cohort near the start of dialysis and at a 9- to 12-month follow-up. Logistic regression was used to investigate the risk of scoring lower on a cognitive function measure at follow-up as a function of self-reported sleep difficulty, controlling for patients’ sociodemographic, clinical and treatment characteristics, including depressed mood. Results At follow-up, cognitive function scores were lower among 35.8% of the cohort. Patients with self-reported persistent sleep difficulty had the lowest average cognitive function score. Men with reported persistent sleep difficulty, regardless of presence of depressed mood, had a significantly increased risk of a lower cognitive function score at follow-up. Women with reported persistent sleep difficulty as well as depressed mood had significantly increased risk of a lower cognitive function score. Conclusion The potential impact of sleep difficulty and depressed mood on the cognitive function of dialysis patients emphasizes the importance of evaluating and treating these risks and highlights the value of continued research to improve our understanding and management of these issues.