Introduction: No data are available about the relationship between sleep apnea (SA) and recurrent stroke and mortality from population-based studies, large samples, or ethnically diverse populations.
Methods: In the Brain Attack Surveillance in Corpus Christi (BASIC) project, we identified patients with ischemic stroke between 2010-2015. Subjects who enrolled were offered screening for SA with the ApneaLink Plus device from which an apnea-hypopnea index (AHI) was derived (≥10 defined SA). Demographics and baseline characteristics were determined from chart review and interview. Recurrent ischemic stroke was identified through active and passive surveillance and confirmed by study neurologists. All-cause mortality was identified through Texas Department of State Health Services records. Cox proportional-hazards models were used to assess the association between AHI (modeled linearly) and combined ischemic stroke recurrence and mortality unadjusted and adjusted for multiple potential confounders.
Results: Of the 842 subjects, the median age was 65 (IQR: 57, 76), 47% were female, 58% were Mexican American, and 34% were non-Hispanic white. The median AHI was 14 (IQR: 6, 26); 63% had SA. SA was associated with male sex, Mexican American ethnicity, being insured, nonsmoking status, diabetes, hypertension, lower educational attainment, and higher BMI. In the time period (median time to event 584 days), 90 (10.7%) recurrent strokes and 125 (14.8%) deaths occurred with a cumulative incidence of recurrence or death of 202 (24%). AHI was associated with the combined endpoint in unadjusted (HR=1.09 per one unit increase in AHI (95%CI: 1.08, 1.10)) and fully adjusted models (HR=1.09 (95%CI: 1.08, 1.10)). Mexican American ethnicity was associated with the endpoint (HR=1.71 (95%CI: 1.16, 2.54) in the fully adjusted model.
Conclusion: SA is associated with the combined endpoint of recurrent ischemic stroke and mortality in this population-based study. Mexican Americans are also at higher risk of recurrent stroke and death following ischemic stroke than non-Hispanic whites. SA may therefore represent an important modifiable risk factor for poor stroke outcomes and a target to reduce ethnic stroke disparities.