Worse Outcome after Stroke in Patients with Obstructive Sleep Apnea: An Observational Cohort Study

Abstract

To evaluate the risk and presence of obstructive sleep apnea (OSA) in patients presenting with acute ischemic stroke, and examine the correlation of OSA with age, sex, ischemic stroke subtype, disability, and death, a prospective cohort study was conducted in all consecutive patients presenting with acute ischemic stroke between June 2007 and March 2008. Exclusion criteria were age < 18 years, refusal of consent for the study, and incomplete questionnaire. The Berlin Sleep Questionnaire was used to identify patients at high risk for OSA. A total of 174 patients with acute ischemic stroke were included; 130 (74.7%) had a modified Rankin Scale (mRS) score ≥ 3 at dismissal, and 11 patients (6.3%) died within 1 month. The Berlin Sleep Questionnaire identified 105 patients (60.4%) at high risk for OSA, along with 7 patients (4%) with a previous diagnosis of OSA. Those with a previous diagnosis of OSA were more likely to die within the first month after stroke (relative risk, 5.3; 95% confidence interval, 1.4-20.1) compared with those without OSA. Patients at high risk for OSA did not demonstrate increased mortality at 30 days (P = 1.0). In multivariate analysis, after adjusting for age and National Institutes of Health Stroke Scale score, previous diagnosis of OSA was an independent predictor of worse functional outcome, that is, worse mRS score at hospital discharge (P = .004). The mRS score was 1.2 points higher (adjusted R², 40%) in those with OSA. Our findings suggest that patients considered at high risk for ischemic stroke should be screened for OSA, the prevalence of which may be as high as 60%. Those with definitive diagnosis of OSA before stroke are at increased risk of death within the first month after an acute ischemic stroke.