Abstract
BACKGROUND: Clinical significance of objectively measured poor sleep quality (SQ) as a risk for cardiovascular disease (CVD) events is not well known in hemodialysis (HD) patients, independently of sleep-related breathing disorders (SRBDs) and sleep-related metabolic abnormality. METHODS: The present study investigated baseline levels of objective sleep architecture together with obstructive sleep apnea (OSA) and central sleep apnea (CSA) using polysomnography in 88 HD study participants (M/F, 56/32; age 68.4 ± 9.3). Then, HD study participants were monitored for the occurrence of new-onset CVD events with a median (range) follow-up period of 33 (1-64) months. RESULTS: Among various measures of SQ, log (REM sleep latency [REM-SL]) (interval between sleep-onset and the first REM period) alone correlated in negative manners with triglycerides and non-HDL-C in all study participants and with fasting plasma glucose and HbA1c in study participants with type-2 diabetes mellitus. In the Kaplan-Meier analysis, HD study participants with shorter REM-SL had a significantly higher rate of new-onset CVD events than those with longer REM-SL. Stepwise logistic regression analysis and multivariate Cox proportional hazard regression analysis identified shorter REM-SL as an independent risk factor for the development of a new-onset CVD events, independent of mean oxygen saturation, log (AHI+1), log (central AHI+1), diabetes mellitus, CVD history, systolic blood pressure, statins use, and non-HDL-C. CONCLUSIONS: The present study demonstrated that reduction of REM-SL is independently associated with a higher rate of new-onset of CVD events, independent of SRBDs (OSA and CSA) and diabetes mellitus, non-HDL-C in HD study participants, suggesting impaired SQ as a potential CVD risk factor, and thus a definite treatment target to protect against CVD specifically in HD study participants. REM-SL might be a new risk factor of CVD events in HD patients with SRBDs.