Comparative Effectiveness of Oral Antiplatelet Agents in Patients with Acute Coronary Syndrome

In randomized controlled trials, prasugrel and ticagrelor reduced cardiovascular complications in patients with acute coronary syndrome (ACS) compared with clopidogrel. However, limited head-to-head comparisons have been conducted across the three antiplatelet agents using real-world data. The aim of this study was to compare clinical outcomes of three strategies during a 1-year period after percutaneous coronary intervention (PCI).

Rates of all-cause and acute myocardial infarction (AMI) hospitalizations were compared retrospectively using an insurance claims database. Patients who filled a prescription for an oral antiplatelet agent between September 2011 and December 2013 for post ACS-PCI care were identified. Time to all-cause and AMI hospitalization for a 365-day postdischarge period was compared using Cox proportional hazard models controlling for potential confounders within a propensity score matched cohort.

A matched cohort of 9504 clopidogrel, 7128 prasugrel, and 2376 ticagrelor patients was analyzed. The 1-year hazard ratio (HR) for the two newer agents versus clopidogrel was 0.84 (0.78-0.91). The HR for the newer agents versus clopidogrel of admission with AMI as the primary diagnosis was 0.78 (0.61-1.03), and for AMI as any diagnosis during a hospitalization was 0.88 (0.77-1.00). The HR of all-cause admission for ticagrelor versus prasugrel was 0.97 (0.84-1.13), and the HRs of AMI-related admission were not statistically significant between the two agents. Robustness checks across statistical methods to control for potential confounders did not influence the conclusion.

This real-world study demonstrated that use of the newer agents following PCI was associated with a decrease in all-cause and AMI-related hospitalizations. However, no significant difference was found in the rate of admission between ticagrelor versus prasugrel. Due to concerns regarding statistical power, future studies should examine larger cohorts to obtain more precise estimates for AMI hospitalization for ticagrelor and prasugrel.