Comparative Effectiveness of Ticagrelor vs. Prasugrel in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

<jats:p> Background: Ticagrelor and prasugrel are recommended P2Y <jats:sub>12</jats:sub> inhibitors for patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI), yet uncertainty persists regarding their direct comparative evidence and guideline recommendations differ. Methods: We conducted a multinational retrospective new-user cohort study across 7 claims and electronic health record databases. Adults with ACS undergoing first PCI who initiated ticagrelor or prasugrel were included; patients with prior major ischemic or hemorrhagic events or oral anticoagulant use were excluded. The primary outcome was 1-year major adverse cardiovascular events (MACE: all-cause mortality, acute myocardial infarction, or stroke). Secondary outcomes included net adverse clinical events (NACE) and individual components. Propensity scores were estimated using large-scale L1-regularized logistic regression and applied through stratification. Prespecified diagnostics (covariate balance, empirical equipoise, and systematic error) determined eligibility of each database for inclusion in meta-analysis. Database-specific hazard ratios (HRs) were combined using Bayesian random-effects meta-analysis. Results: Among 7 participating databases, 3 met prespecified diagnostic criteria and were included in the primary meta-analysis, comprising 133,718 patients from one nationwide Korean claims database and two U.S. commercial claims databases (ticagrelor, 109,639; prasugrel, 24,079). For 1-year MACE, the pooled HR for ticagrelor versus prasugrel was 1.28 (95% credible interval [CrI], 0.89-1.88), with substantial between-database heterogeneity. Sensitivity analyses across alternative time-at-risk definitions and propensity score matching were consistent. No statistically credible differences were observed for NACE (HR 1.23, CrI 0.88-1.75), all-cause mortality (HR 1.17, CrI 0.78-1.77), cardiovascular mortality (HR 1.23, CrI 0.81-1.87), ischemic events (HR 1.28, CrI 0.88-1.90), hemorrhagic events (HR 1.01, CrI 0.72-1.39), acute myocardial infarction (HR 1.30, CrI 0.88-1.94), stroke (HR 1.09, CrI 0.73-1.58), or gastrointestinal bleeding (HR 1.04, CrI 0.77-1.41). In a post hoc meta-analysis restricted to the two U.S. databases, the pooled HR for 1-year MACE was 1.49 (95% CrI 1.05-2.10). Conclusions: In this pre-specified multinational observational study, no statistically credible difference in 1-year MACE was observed between ticagrelor and prasugrel in patients with ACS undergoing PCI. However, substantial cross-database heterogeneity warrants further investigation into context-specific comparative effectiveness and safety. </jats:p>