ABSTRACT NUMBER: ESOC2026A1364 INCREASED RISK OF ISCHEMIC EVENTS IN PATIENTS WITH STROKE TREATED WITH CLOPIDOGREL AND A POTASSIUM-COMPETITIVE ACID BLOCKER OR PROTON PUMP INHIBITOR

Abstract Background and aims This study evaluated the effectiveness and safety of potassium-competitive acid blockers (P-CABs) and proton pump inhibitors (PPIs) co-administered with clopidogrel in patients with ischemic stroke. Methods This population-based, longitudinal, retrospective cohort study used the Korean National Health Insurance Service database, covering 51.4 million individuals from 2016 to 2022. Propensity-score matching (PSM) compared the 6-month incidence of major adverse cardiovascular events (MACE, including MI, stroke recurrence, and all-cause mortality) among three cohorts: clopidogrel alone, clopidogrel+P-CAB, and clopidogrel+PPI. Results Between 2017 and 2021, 40 752 of 65 180 incident stroke patients (62.5%) received clopidogrel. A total of 6680 patients (16.4%) formed the clopidogrel-alone cohort, 578 (1.4%) the clopidogrel+P-CAB cohort, and 8806 (21.6%) the clopidogrel+PPI cohort. During the follow-up period, stroke recurred in 268 patients (4.0%) receiving clopidogrel alone, 26 patients (4.5%) receiving clopidogrel+P-CAB, and 431 patients (4.9%) receiving clopidogrel+PPI. After PSM, the clopidogrel+P-CAB cohort showed a higher risk of MACE (hazard ratio [HR] 2.40; 95% confidence interval [CI] 1.18–4.85) and stroke recurrence (HR 2.64; 95% CI 1.27–5.47) than the clopidogrel-alone cohort. The clopidogrel+PPI cohort also had an increased risk of MACE (HR 1.38; 95% CI 1.17–1.63) and stroke recurrence (HR 1.41; 95% CI 1.20–1.67) relative to clopidogrel alone. Conclusions Concomitant use of P-CABs or PPIs with clopidogrel was associated with an increased risk of ischemic events in patients with stroke. P-CABs or PPIs should therefore be prescribed cautiously for stroke patients treated with clopidogrel. Conflict of interest Kwang-Yeol Park: nothing to disclose; Jung-Hwa Hong: nothing to disclose; Seong-Hun Parknothing to disclose; Eun-Young Kimnothing to disclose;