Efficacy and safety of ticagrelor versus clopidogrel in acute coronary syndrome in Taiwan

Background The efficacy and safety of ticagrelor compared with clopidogrel in acute coronary syndrome has not previously been evaluated in an Eastern Asian population, which is recognized to have a different response to P2Y12 antagonists compared with the Caucasian population in real-life situations. Methods A multicenter retrospective pilot study was performed to evaluate 928 consecutive patients with acute coronary syndrome, receiving aspirin and one P2Y12 antagonist (324 ticagrelor or 604 clopidogrel). Using propensity score matching, 448 patients were selected and divided into two equal groups. Kaplan–Meier analysis was used to study patient survival and event-free status using the log-rank test. Independent covariates were identified using univariate in a multivariate Cox proportional hazard model. Results In the overall cohort, significant differences were observed for certain variables between the two groups. During the mean 164.3 (±116.4)-day follow-up in the overall cohort, ticagrelor treatment had no significant effect on the primary efficacy endpoint (myocardial infarction, stroke, or vascular death); however, in the matched cohort, ticagrelor showed a lower incidence of primary endpoint (hazard ratio: 0.56; 95% confidence interval: 0.30–1.04; p = 0.07) and stroke (hazard ratio: 0.15; 95% confidence interval: 0.02–1.24; p = 0.08) with marginal statistical significance, and a similar bleeding rate. The protective effect of ticagrelor treatment was consistent for all subgroups. More patients treated with ticagrelor experienced dyspnea (21.0% vs. 11.6%, p = 0.007), and P2Y12 antagonist treatment was consequently discontinued. Conclusion Ticagrelor treatment could provide a marginally favorable effect at the expense of an increased risk of dyspnea in real-life situations. This pilot study provides a scientific basis to call for a larger, suitably powered Phase 4 prospective or observational study in this ethnic population.