Nocturnal hypoxemia and periodic limb movement predict mortality in patients on maintenance hemodialysis

Background and objectives: Sleep disorders, including sleep-disordered breathing and periodic limb movements during sleep, are associated with an increased risk for cardiovascular diseases, which are the leading causes of death in patients with ESRD. This study investigated the association between sleep disorders and mortality in patients with ESRD. Design, setting, participants, & measurements: Thirty patients on maintenance hemodialysis, who were clinically stable for >2 months, underwent overnight polysomnography to evaluate sleep parameters. Results: All patients were followed for a median of 48 months (range: 14 to 62 months), and 14 of them died during the follow-up period. Among the sleep parameters, the percent of sleep time with arterial oxygen saturation <90% (T <90%), mean arterial oxygen saturation, and periodic limb movement index score were associated with significant increases in the risk of death. However, associations of the apnea-hypopnea index or oxygen desaturation index with mortality were NS. The hazard ratios (95% confidence intervals) for death per one SD increment in the log-transformed T <90% and periodic limb movement index score were 2.10 (1.06 to 4.15) and 2.48 (1.11 to 5.52), respectively, after adjusting for age. Conclusions: We found that nocturnal hypoxemia and periodic limb movement during sleep, rather than apnea itself, were associated with an increased risk for death in patients with ESRD. However, conclusions from this study should be drawn with caution, because they are limited by the small sample size.