Association of Rapid Eye Movement Sleep With Mortality in Middle-aged and Older Adults.

Importance: Rapid eye movement (REM) sleep has been linked with health outcomes, but little is known about the relationship between REM sleep and mortality. Objective: To investigate whether REM sleep is associated with greater risk of mortality in 2 independent cohorts and to explore whether another sleep stage could be driving the findings. Design, Setting, and Participants: This multicenter population-based cross-sectional study used data from the Outcomes of Sleep Disorders in Older Men (MrOS) Sleep Study and Wisconsin Sleep Cohort (WSC). MrOS participants were recruited from December 2003 to March 2005, and WSC began in 1988. MrOS and WSC participants who had REM sleep and mortality data were included. Analysis began May 2018 and ended December 2019. Main Outcomes and Measures: All-cause and cause-specific mortality confirmed with death certificates. Results: The MrOS cohort included 2675 individuals (2675 men [100%]; mean [SD] age, 76.3 [5.5] years) and was followed up for a median (interquartile range) of 12.1 (7.8-13.2) years. The WSC cohort included 1386 individuals (753 men [54.3%]; mean [SD] age, 51.5 [8.5] years) and was followed up for a median (interquartile range) of 20.8 (17.9-22.4) years. MrOS participants had a 13% higher mortality rate for every 5% reduction in REM sleep (percentage REM sleep SD = 6.6%) after adjusting for multiple demographic, sleep, and health covariates (age-adjusted hazard ratio, 1.12; fully adjusted hazard ratio, 1.13; 95% CI, 1.08-1.19). Results were similar for cardiovascular and other causes of death. Possible threshold effects were seen on the Kaplan-Meier curves, particularly for cancer; individuals with less than 15% REM sleep had a higher mortality rate compared with individuals with 15% or more for each mortality outcome with odds ratios ranging from 1.20 to 1.35. Findings were replicated in the WSC cohort despite younger age, inclusion of women, and longer follow-up (hazard ratio, 1.17; 95% CI, 1.03-1.34). A random forest model identified REM sleep as the most important sleep stage associated with survival. Conclusions and Relevance: Decreased percentage REM sleep was associated with greater risk of all-cause, cardiovascular, and other noncancer-related mortality in 2 independent cohorts.

Prognostic impact of central sleep apnea in patients with heart failure.

BACKGROUND: Central sleep apnea (CSA) is common in patients with heart failure (HF). Earlier studies investigating the influence of CSA on mortality in HF patients, however, have yielded contradictory results. METHODS AND RESULTS: In a prospective study involving 267 patients with left ventricular (LV) ejection fractions ≤50%, we performed polysomnography and compared heart transplant-free survival rates between patients with no or mild CSA (apnea-hypopnea index [AHI] ≤15/h) and those with moderate CSA (AHI 15.1-30/h) or severe CSA (AHI >30/h). During 43 ± 18 months' mean follow-up, 67 patients (25%) died and 4 patients (1%) underwent heart transplantation. Multivariate Cox analysis identified age, male sex, chronic kidney disease, and decreased LV ejection fraction, but not moderate CSA or severe CSA, as predictors of transplant-free survival. CONCLUSIONS: In patients with stable HF, moderate CSA as well as severe CSA do not appear to predict transplant-free survival independently from confounding factors.

Incidence of serious adverse events during nocturnal polysomnography.

OBJECTIVES: The purpose of the study was to verify whether minimal concern is warranted in regard to serious adverse effects in the sleep laboratory. DESIGN: A prospective multicenter study PARTICIPANTS: Three scoring teams for 17 sleep laboratories. METHODS: Reports of adverse events occurring during polysomnography or identified upon scoring a study were collected over an 18-month time period. Incidence of mortality and adverse events were evaluated using a binomial distribution based on the Bernoulli process. RESULTS: Of 16,084 studies, the mortality rate during or 2 weeks after an adverse event, as noted, was 0.006%, and the overall rate of adverse events was 0.35%. CONCLUSIONS: Adverse event rates are low; however, procedures for handling medical emergencies or adverse events during or after polysomnography are prudent, and those studies performed for research should include preparedness for the possibility of adverse events.