Correlation between physical functioning and sleep disturbances in hemodialysis patients

The study set out to investigate the relationship between physical functioning, inflammatory status, and sleep disturbance in a chronic hemodialysis (HD) population. Forty-six maintenance HD patients from the McGill University Health Centre were enrolled in this study between October 2005 and 2006. The well-validated Human Activity Profile (HAP) questionnaire and the RAND 36-item survey were used to assess physical functioning. Subjects were given the Pittsburgh Sleep Quality Index (PSQI) survey to evaluate the degree of sleep disturbance. Inflammatory status was assessed with the average value of serial C-reactive protein (CRP) levels for each patient, over a period of 12 months before their enrollment in the study. A multivariate logistic regression model was created for these analyses to control for potential confounders, including dialysis adequacy, inflammation, and hemoglobin. Seventy-six percent of the study population had poor sleep as per the Pittsburgh Sleep Quality Index (PSQI score > or = 5). In addition, 65% of subjects had high CRP values (>5 mg/L). On univariate analysis, both a CRP >5 mg/L and a lower adjusted activity score (AAS) on the HAP were significantly associated with poor sleep (PSQI score > or = 5). Multivariate logistic analysis demonstrated that the AAS remained significantly associated with poor sleep, with a 6% decrease in the odds of poor sleep for each score increase in the AAS of the HAP. Poor physical functioning in chronic HD patients, as measured by the HAP, is associated with sleep disturbance, after controlling for inflammation and dialysis adequacy.