Background and Purpose--There are limited and conflicting data on gender differences in clinical outcomes among patients with symptomatic intracranial arterial stenosis. This study examined gender differences in patients enrolled in the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) Study.

Methods--Participants were 569 men and women with symptomatic intracranial arterial stenosis. They were followed-up for the occurrence of ischemic stroke and the combined end point of stroke or vascular death from February 1999 through July 2003 (mean follow-up, 1.8 years).

Results--Two-year rates of the primary end point were 28.4% and 16.6% for women and men, respectively. Cumulative probabilities of the outcomes over time were estimated by the Kaplan-Meier product-limit method and were compared between men and women with the use of the log-rank test. Cox proportional hazards regression analyses were used to estimate the hazard ratio of gender (women to men) for ischemic stroke and for the primary end point. The probabilities of ischemic stroke (P=0.005) and of the combined end point of stroke or vascular death (P=0.017) over time were significantly higher in women than men. Women had a greater multivariate-adjusted risk for ischemic stroke (HR, 1.85; 95% CI, 1.14 to 3.01; P=0.013) and for the combined end point of stroke or vascular death (HR, 1.58; 95% CI, 1.01 to 2.48; P=0.045).

Conclusions--Women with symptomatic intracranial arterial stenosis are at significantly greater risk for ischemic stroke and for the combined end point of stroke or vascular death. These findings suggest the need for vigorous screening of risk factors and for aggressive management of risk factors and stroke in women. They also suggest the need to ensure adequate numbers of women in clinical trials designed to explore new and promising therapies for intracranial arterial stenosis.