Sex differences in the risk of recurrent ischemic stroke after ischemic stroke and transient ischemic attack

Abstract

Background Sex differences in stroke outcomes have been noted, but whether this extends to stroke recurrence is unclear. We examined sex differences in recurrent stroke using data from the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial. Patients and methods We assessed the risk of recurrent stroke in women compared to men using data from the POINT trial. Adults >18 years old were randomized within 12 hours of onset of minor ischemic stroke or transient ischemic attack (TIA), and followed for up to 90 days for ischemic stroke, our primary outcome. We used Cox proportional hazards model adjusted for demographics and stroke risk factors to evaluate the association between sex and stroke recurrence. We used interaction term testing and prespecified subgroup analyses to determine if the association between sex and recurrent stroke differed by age (<60 versus >60 years old), locale (US versus non-US), and index event type (stroke versus TIA). Last, we evaluated whether sex modified the effect of common stroke risk factors on stroke recurrence. Results Of 4,881 POINT trial participants with minor stroke or high-risk TIA, 2,195 (45%) were women. During the 90-day follow-up period, 267 ischemic strokes occurred; 121 were in women and 146 in men. The cumulative risk of recurrent ischemic stroke was not significantly different among women (5.76%; 95% CI, 4.84%–6.85%) compared to men (5.67%; 95% CI, 4.83%–6.63%). Women were not at a different risk of recurrent ischemic stroke compared to men (hazard ratio [HR], 1.02; 95% CI, 0.80–1.30) in unadjusted models or after adjusting for covariates. However, there was a significant interaction of age with sex (P=0.04). Among patients <60 years old, there was a non-significantly lower risk of recurrent stroke in women compared to men (HR 0.66; 95% CI 0.42–1.05). Last, sex did not modify the association between common stroke risk factors and recurrent stroke risk. Discussion and Conclusion Among patients with minor stroke or TIA, the risk of recurrent ischemic stroke and the impact of common stroke risk factors did not differ between men and women.