Sleep disordered breathing with excessive daytime sleepiness is a risk factor for mortality in older adults

Abstract

Study objectives: Excessive daytime sleepiness (EDS) is associated with increased mortality in older adults, yet sleep disordered breathing (SDB), a common cause of sleepiness, has not been shown to increase mortality in older adults. This study examined the relationship between daytime sleepiness, SDB, self-report sleep parameters, and mortality in older adults.

Design: Longitudinal cohort study.

Setting: Clinical and Translational Research Center, at-home testing.

Participants: 289 study participants (age >65, no dementia or depression at the time of enrollment) classified as having EDS (n=146) or not (n=143).

Measurements and results: Study participants underwent in-lab polysomnography and multiple sleep latency testing at cohort inception. Survival analysis was conducted, with an average follow-up of 13.8 years. Excessive daytime sleepiness was associated with an unadjusted mortality hazard ratio of 1.5 (95% CI 1.1-2.0). The unadjusted mortality hazard ratio for study participants with both EDS and SDB (apnea-hypopnea index ≥20 events/h) was 2.7, 95% CI: 1.8-4.2. These findings persisted with an adjusted mortality hazard ratio of 2.3, 95% CI: 1.5-3.6 in the final model that included other covariates associated with increased mortality (sleep duration >8.5 h, self-reported angina, male gender, African American race, and age).

Conclusion: The presence of SDB is an important risk factor for mortality from excessive daytime sleepiness in older adults. In the presence of SDB at an AHI ≥20 events/h, EDS was associated with an increased all-cause mortality risk in older adults, even when adjusting for other significant risk factors, such as prolonged sleep duration. In older patients who had SDB without EDS, or EDS without SDB, there was no increased all-cause mortality rate.

Keywords: Sleep disordered breathing; aged; daytime sleepiness; longitudinal; mortality.

Figure 1

Hazard ratios for mortality from combined EDS and SDB at various levels of SDB (as defined by the apnea-hypopnea index, [AHI, events/h]). The reference category is an AHI < 5 events/h. Bars represent 95% confidence intervals. Dark gray columns indicate unadjusted analyses. Light gray columns indicate adjusted analyses that include covariates from the final model shown in Table 2.

Figure 2

Survival curve as a function of excessive daytime sleepiness (EDS) and sleep disordered breathing (SDB) status. Solid line: EDS+/SDB+. Dashed line: EDS-/SDB+. Long-short dashed line: EDS+/SDB-. Dotted line: EDS-/SDB-. Dark circles: censored EDS+/SDB+. Open circles: censored EDS+/SDB-. Open squares: censored EDS-/SDB+. Open triangles: censored EDS-/SDB-.

Figure 3

Hazard ratios for different categories of EDS (EDS) and SDB (SDB, defined as an AHI ≥ 20 events/h). The reference group is the EDS-/SDB- category. Bars represent 95% confidence intervals. Dark gray columns indicate unadjusted analyses. Light gray columns indicate adjusted analyses that include covariates from the final multivariate model.