Joint effects of OSA and self-reported sleepiness on incident CHD and stroke

Background: Although excessive daytime sleepiness (EDS) is a common symptom of obstructive sleep apnea (OSA), and both EDS and OSA have separately been associated with increased risk of cardiovascular disease (CVD), their joint association with CVD risk is unknown.

Methods: Among 3874 Sleep Heart Health Study (SHHS) participants without prevalent CVD, moderate to severe OSA was defined by an apnea hypopnea index (AHI) ≥ 15 on an in-home polysomnography. EDS was defined as an Epworth Sleepiness Scale score ≥11. Incident CVD events included total CVD events (coronary heart disease (CHD) and stroke), as well as CHD and stroke separately. Cox proportional hazards models adjusted for age, sex, alcohol, smoking, and body mass index.

Results: Compared to those with AHI <15, the hazard ratios (95% CI) for the association of moderate-severe OSA (AHI ≥15) were as follows: CVD 1.06 (0.85-1.33); CHD 1.08 (0.85-1.33); and stroke 1.18 (0.75-1.84). Weak associations between EDS and CVD risk = [1.22 (1.01-1.47)] and CHD risk [1.25 (1.02-1.53)] were present, however there were none for stroke risk [1.10 (0.75-1.63)]. When jointly modeled, both AHI ≥15 and EDS (compared with having AHI <15 and no EDS) was associated with HRs of 1.26 (0.91-1.73) for CVD, 1.24 (0.87-1.75) for CHD and 1.49 (0.78-2.86) for stroke. There were no statistically significant interactions between daytime sleepiness and OSA on the multiplicative or additive scales.

Conclusions: Having both EDS and moderate-severe OSA was not associated with an increased risk of CVD in the SHHS data.