Effectiveness of new antiplatelets in the prevention of recurrent myocardial infarction.

Objective: To compare ticagrelor and prasugrel with clopidogrel for recurrent fatal and non-fatal myocardial infarction (reMI) in real-life conditions.

Methods: Case-referent study using the Pharmacoepidemiological General Research eXtension (PGRx)-acute coronary syndrome (ACS) registry. Cases were patients with reMI from a cohort with index ACS or external to the cohort (same sites). Referents from the cohort, without recurrent event, were matched on index ACS type and date, age and sex with reMI cases. Multivariate conditional logistic regression assessed the OR (95% CI) for reMI associated with ticagrelor and prasugrel vs clopidogrel, adjusted for aspirin use and cardiovascular risk factors.

Results: 1047 cases and 2234 matched referents were included. Compared with clopidogrel, ticagrelor and prasugrel were associated with respective ORs of 0.65 (95% CI 0.52 to 0.81) and 0.71 (95% CI 0.53 to 0.96) for reMI occurrence. ORs for ticagrelor and prasugrel vs clopidogrel were: 0.50 (95% CI 0.38 to 0.67) and 0.66 (95% CI 0.45 to 0.95), 0.39 (95% CI 0.24 to 0.62) and 0.44 (95% CI 0.26 to 0.75), 0.63 (95% CI 0.43 to 0.92) and 1.20 (95% CI 0.69 to 2.07), 1.11 (95% CI 0.72 to 1.72) and 0.82 (95% CI 0.44 to 1.54) when index ACS was a first MI, a first ST-elevated MI (STEMI), a first non-STEMI and a recurrent ACS, respectively, and 0.63 (95% CI 0.45 to 0.87) and 0.77 (95% CI 0.41 to 1.45) for patients aged ≥70  years.

Conclusions: This real-world study showed a significant reduction of reMI with new antiplatelets compared with clopidogrel, ticagrelor being associated with a greater decrease of risk notably for first, either STEMI or non-STEMI. The larger magnitude of effect may be attributed to potential residual confounding or higher effectiveness compared with efficacy reported in trials (EMA Post Authorisation Study Registry Number EUPAS5905).