Sex Difference in the Impact of Dual Antiplatelet Therapy using Cilostazol for Secondary Stroke Prevention: A Sub-Analysis of CSPS.com

Aim: Although some sex differences in stroke have been reported, differences in the effects of antiplatelet therapy for secondary stroke prevention have not been clarified. Methods: In the Cilostazol Stroke Prevention Study combination trial, patients with high-risk, non-cardioembolic ischemic stroke between 8 and 180 days after onset treated with aspirin or clopidogrel alone were recruited and randomly assigned to receive either monotherapy or dual antiplatelet therapy (DAPT) using cilostazol and followed up for 0.5–3.5 years. The primary efficacy outcome was recurrence of ischemic stroke. The safety outcome was severe or life-threatening hemorrhage. Outcomes were analyzed by sex. Results: A total of 1,320 male patients and 558 female patients were included. The male patients had more risk factors than the female patients. In male patients, the primary endpoint occurred at a rate of 2.0 per 100 patient-years in the DAPT group and 5.1 per 100 patient-years in the monotherapy group (hazard ratio (HR), 0.40; 95% confidence interval (CI), 0.23–0.68). In male patients, DAPT prolonged the time to recurrent stroke by 4.02-fold (95% CI, 1.63–9.96) compared with monotherapy. In female patients, the average annual event rates were 2.7 per 100 patient-years in the DAPT group and 3.3 per 100 patient-years in the monotherapy group (HR, 0.82; 95% CI, 0.37–1.84). Safety outcomes did not differ significantly in both male and female patients. Conclusions: Long-term DAPT using cilostazol reduced the recurrence of ischemic stroke and prolonged the recurrence-free time in male patients, but not in female patients.