Potential novel predictors of mortality in end-stage renal disease patients with sleep disorders

Patients with end-stage renal disease (ESRD) have an annual mortality rate exceeding 20%, although some survive many years. The ESRD population has a high incidence of sleep disorders, including sleep apnea and periodic limb movements in sleep (PLMS). Sleep disorders result in sleep deprivation, which can negatively affect immune function and cardiovascular-related outcomes, common causes of death in patients with ESRD. This study examined predictors of mortality in patients with ESRD with sleep problems. Twenty-nine consecutive patients with ESRD reporting disrupted sleep or daytime sleepiness were studied by all-night polysomnography. All patients were followed up until death, transplantation, or study termination. Among the variables studied, including such previously reported predictors as serum albumin level, urea reduction ratio, and hematocrit, only the PLMS index (PLMSI), arousing PLMSI (APLMSI), and total number of arousals per hour of sleep significantly predicted mortality. The 20-month survival rate with a PLMSI less than 20 was greater than 90% versus 50% for a PLMSI of 20 or greater (exact log-rank, P = 0.007). For the deceased versus survivor groups, mean PLMSI was 119.1 versus 19.8 (P = 0.01) and APLMSI was 48.1 versus 7.8 (P = 0.00006), with a mean survival of 10.3 versus greater than 25.5 months, respectively (P = 0.001). Median survival of patients with a PLMSI greater than 80 was only 6 months. PLMSI, APLMSI, and total arousals per hour of sleep were strongly associated with mortality in patients with ESRD with sleep disorders independent of other factors and may be novel predictors of near-term mortality.