Effect of Antiplatelet Therapy (Aspirin + Dipyridamole Versus Clopidogrel) on Mortality Outcome in Ischemic Stroke: a cohort study

The optimal regimen of antiplatelet therapy for secondary prevention in noncardioembolic ischemic stroke remains controversial. We aimed to determine which regimen was associated with the greatest reduction in adverse outcomes. We analysed prospectively collected data from the Norfolk and Norwich University Hospital Stroke Register. The sample population consisted of 3,572 participants (mean age 74.96 ± 12.67) with ischemic stroke, who were consecutively admitted between 2003 and 2015. Patients were placed on one of three antiplatelet regimens at hospital discharge; aspirin monotherapy, aspirin plus dipyridamole and clopidogrel. Clopidogrel and aspirin plus dipyridamole were compared to aspirin. A direct comparison between clopidogrel and aspirin plus dipyridamole was also performed. Outcomes included all-cause mortality and a combined end point of all-cause mortality and incidence of major adverse cardiac events (stroke or myocardial infarction). Cox-regression models adjusted for potential confounders at the following time periods after discharge; 0 to 90 days, 91 to 365 days, and 1 to 3 years. Aspirin plus dipyridamole was associated with a lower risk of mortality at 0 to 90 days; hazard ratio (HR) 0.62 (0.43 to 0.91). Clopidogrel was associated with a lower risk of mortality at 1 to 3 years; HR of 0.39 (0.26 to 0.60). Similar HRs were observed for the corresponding time points in the composite outcome. In conclusion, patients with noncardioembolic stroke may gain maximum benefits from aspirin plus dipyridamole initially (≤1 year) with a subsequent switch to clopidogrel, with regard to mortality and major adverse cardiac eventsoutcomes.