Real-World Postdischarge P2Y12 Inhibitor Use After Ischemic Stroke and Transient Ischemic Attack, 2020 to 2024

Background: P2Y12 inhibitor acquisition and continuation after ischemic stroke or transient ischemic attack (TIA) are incompletely characterized. Objective: To describe postdischarge clopidogrel and ticagrelor uptake, persistence, switching, bleeding diagnoses, and trends. Methods: This retrospective descriptive cohort study used US claims (2020-2025). Adults with a first qualifying inpatient ischemic stroke or inpatient/emergency-department TIA from July 2020 through December 2024 were included. Fills were assessed through 90 days. Persistence and 1-year bleeding diagnoses were evaluated among continuously enrolled initiators; switching was assessed through follow-up of 365 days. Results: Among 45 763 patients, 8667 (18.9%) filled a P2Y12 inhibitor within 30 days: 8226 clopidogrel (94.9% of initiators) and 441 ticagrelor (5.1%). Among 5641 continuously enrolled initiators, clopidogrel versus ticagrelor persistence was 66.3% versus 78.3% at day 90 and 50.5% versus 59.6% at day 180; it was low for both at day 365. Switching occurred in 2.9%; 23.8% of ticagrelor initiators later filled clopidogrel versus 1.7% in the reverse direction. Crude 1-year intracerebral hemorrhage and gastrointestinal bleeding diagnosis rates were 2.6% and 5.8%. Overall uptake rose from 18.3% in July to December 2020 to 20.9% in 2024. Claims did not reliably capture over-the-counter aspirin, clinical eligibility, ingestion, or reasons for changes. Conclusion and Relevance: Fewer than 1 in 5 adults with coded ischemic stroke or TIA filled a P2Y12 inhibitor within 30 days. These data benchmark outpatient acquisition and persistence, not guideline adherence or comparative effectiveness.