ABSTRACT NUMBER: ESOC2026A411 EVALUATING REAL-WORLD OUTCOMES OF SINGLE VERSUS DUAL ANTIPLATELET THERAPY AFTER AN ISCHAEMIC STROKE: MORTALITY AND MAJOR ADVERSE CARDIOVASCULAR EVENTS

Abstract Background and aims Antiplatelet therapy (APT) is key for preventing morbidity and mortality after IS, with guideline-based single (SAPT) and dual (DAPT) regimens widely used. This study compared real-world outcomes between SAPT and DAPT, identified using a novel method, following an initial IS. Methods This retrospective cohort study used the Healthcare Integrated Research Database, a nationally representative US healthcare database, to identify adults with NCIS from 01/01/16 to 30/06/24. Eligible patients had an IS hospitalisation, no conditions commonly associated with cardioembolic stroke, and continuous enrolment for ≥1 year pre- and ≥1 day post-IS. SAPT and DAPT exposures were defined during the 90-day period post-IS, using prescription claims data, and were used to create a novel, validated method to identify aspirin use in electronic health records (Figure 1). Inverse probability treatment weighting (IPTW) was used to balance differences between groups and compare cumulative incidence curves for outcomes of interest. Results The study included 14,469 individuals with SAPT (53.4%) or DAPT (46.6%) after IS (Figure 2). The IPTW-adjusted 1-year incidence of all-cause death was 3.8% with SAPT and 2.3% with DAPT; average treatment effect, −1.5% (95% CI: −2.0 to −0.8). The incidence of major bleeding was 2.9% with SAPT and 3.5% with DAPT; average treatment effect, 0.6% (0 to 1.3). Rates of stroke were similar between groups (Figure 3). Conclusions In this real-world cohort of patients with IS, a novel aspirin identification method was introduced. Patients receiving DAPT had a lower incidence of all-cause death and MACE, but increased bleeding events compared with those receiving SAPT. Conflict of interest Funding for this study was provided by Bayer AG, Berlin, Germany. M.H., V.H., K.H., and V.W. are employees of Carelon Research, which received research funds from Bayer to perform this research. E.D. and S.C. are employees of Bayer and may own shares or share options in the company. L.L. receives research funding from the National Institutes of Health and receives consulting fees from Bayer. S.Ch. is a consultant to Bayer and Novartis. Figure 1 - belongs to Methods Figure 2 - belongs to Results Figure 3 - belongs to Conclusions