Effect of obstructive sleep apnea on frequency of stroke in patients with atrial fibrillation.

Obstructive sleep apnea (OSA) is an independent risk factor for ischemic stroke that is not included in the usual cardioembolic risk assessments for patients with atrial fibrillation (AF). The aim of this study was to investigate the impact of OSA on stroke rate in patients with AF. Patients with AF and new diagnoses of OSA were identified from retrospective chart review. Those with histories of stroke at the time of the sleep study were excluded. The primary outcome was the incidence of stroke, determined by a physician investigator blinded to the results of polysomnography. Subgroup analysis was performed among different CHADS₂ and CHA₂DS₂-VASc scores. Of 5,138 patients screened for OSA, 402 (7.7%) had AF and 332 (6.4%) met the inclusion criteria. Among the study population, the occurrence of first-time stroke was 22.9%. Ischemic stroke was more common in patients with OSA compared with patients without (25.4% vs 8.2% respectively, p = 0.006). After controlling for age, male gender, and coronary artery disease, the association between OSA and stroke remained statistically significant, with an adjusted odds ratio of 3.65 (95% confidence interval 1.252 to 10.623). A positive dose effect of the apnea-hypopnea index on the rate of stroke was observed (p = 0.0045). Subgroup analysis showed significantly higher rates of stroke in patients with CHADS₂ scores of 0 and CHA₂DS₂-VASc scores of 0 and 1 and co-morbid OSA. In conclusion, OSA in patients with AF is an independent predictor of stroke. This association may have important clinical implications in ischemic stroke risk stratification.