Abstract P645: Sex Differences in the Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) Trial

Abstract

Introduction: Sex differences have been noted in stroke and estrogen is associated with decreased platelet aggregation. The purpose of this study was to assess sex differences in the Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) study. Methods: We performed a secondary analysis of the POINT study. Patients were analyzed by intention to treat group: 1) Males, standard (n=1351) aspirin; 2) Males, intervention (n=1335) clopidogrel+aspirin; 3) Females; standard (n=1098) aspirin; and 4) Females, intervention (n=1097) clopidogrel+aspirin. Groups were compared for baseline demographics via ANOVA followed by Mann Whitney U. A Cox Proportional Hazards Model was used to assess the primary safety and efficacy outcomes. Results: Baseline characteristics were significantly different only for race (p<.001) with white race being most represented. The primary outcome occurred in 6.4% of standard males, 6.7% of standard females, 5.1% of intervention males, and 4.8% of intervention females (p=0.12). Cox models suggest that male intervention participants had lower hazard rate compared to male standard participants (HR=0.79, CI:0.58-1.09) and female intervention participants had a lower hazard compared to male standard (HR=0.76, CI: 0.54-1.07) but this was not statistically significant. Major hemorrhage occurred in 0.4% of standard males, 0.5% of standard females, 0.8% of intervention males, and 1.1% of intervention females (p=0.11). Female intervention subjects had a significantly higher hazard rate of major hemorrhage compared to standard males (HR=2.99, CI:1.06-8.52) with no other between group differences. Conclusion: This study found that there were no significant sex differences in the reduction of recurrent vascular events in the POINT trial. The rate of major hemorrhage was higher in female intervention compared to male standard subjects, but there was no difference in rates between the female groups or the male intervention group. Future studies must provide a sample size with enough power to assess for sex differences to optimize care. Both males and females benefit from combination therapy but the risk of major hemorrhage must be considered.