Background and aim: Excessive daytime sleepiness (EDS) increases cardiovascular risk in the presence of obstructive sleep apnea (OSA). We studied the prognostic role of EDS in OSA on long-term all-cause mortality in a sex-stratified community-based population of hypertensive patients and normotensive controls.

Methods: 341 participants (46.6% hypertensives, 50.7% males, 61.2±6.5 years, body mass index 28.6±4.8 kg/m²) underwent ambulatory polysomnography studies at baseline. Apnea/hypopnea events were defined as a >50% reduction of airflow amplitude or an airflow reduction associated with an oxygen desaturation of >3% or an arousal. A multi-dimensional EDS definition was applied including either an Epworth Sleepiness Scale (ESS) ?10 or self-reported ?moderate/severe/very severe sleepy during the day? in a multiple-choice question.

Results: At baseline, 46.6% had moderate-to-severe OSA (apnea-hypopnea index [AHI] ?20 events/h) and 35.8% had EDS. The mean follow-up time was 15.8±3.9 years and 85 deaths occurred. Compared to the AHI<20 and non-EDS group, moderate-to-severe OSA with EDS was independently associated with greater risk of all-cause mortality (fully adjusted Cox regression model, hazard ratio 2.32 [95%CI: 1.19, 4.54], P=0.014). Sensitivity analysis revealed that EDS defined by the single question (2.26 [1.15, 4.41], P=0.017) but not by the ESS (2.10 [0.93, 4.77], P=0.076) showed significant prognostic value for all-cause mortality. 

Conclusions: OSA with EDS symptoms increased risk of all-cause mortality. A multi-dimensional definition of EDS is important for phenotyping OSA patients at mortality risk.

*JH & BD contributed equally.