Quality of sleep in patients with chronic kidney disease

Background. Sleep disorders are common in patients with renal failure on dialysis; however, the prevalence of 'poor sleep' in patients with chronic kidney disease (CKD) not yet on dialysis is not known. This study aimed to measure the prevalence of 'poor sleep' in CKD patients and to examine the association between quality of sleep and the degree of renal impairment in this population. Methods. Quality of sleep was measured using the Pittsburgh Sleep Quality Index (PSQI) in 120 prevalent CKD patients. Results. Sixty-three subjects (53%) had 'poor sleep' defined as a global PSQI score >5. There was no statistically significant relationship between the global PSQI score and the blood urea nitrogen level (BUN), serum creatinine level or calculated creatinine clearance, but the sleep efficiency component score correlated with BUN (r=0.19, P=0.04) and serum creatinine (r = 0.20, P = 0.03). A history of depression was the only independent predictor of 'poor sleep' (global PSQI > 5). Conclusions. 'Poor sleep' is common in CKD patients. Quality of sleep decreases in the early stages of CKD and does not appear to be associated with the subsequent degree of renal failure. Large prospective longitudinal studies of quality of sleep in CKD patients are needed to confirm the high prevalence of impaired quality of sleep in this population and examine the association between renal function and quality of sleep while controlling for potential confounding variables.