Abstract WP237: Anticoagulant Utilization and Risk of Thromboembolic Events Following Ischemic Stroke Among Adults With Cancer

Abstract

Rationale: Ischemic stroke and cancer frequently coexist, but there are limited data from population-based cohorts regarding prevalence, risk of subsequent thromboembolic events, and treatments. Methods: We leveraged large-scale healthcare data to assess recurrent thromboembolic events in the 6 months following discharge for ischemic stroke among a nationally representative U.S. population with active cancer. Landmark analyses were undertaken with anticoagulant exposure status based on dispensations in the week following hospital discharge. Adjusted hazard ratios (aHRs) were estimated using Cox proportional hazard models with robust variance estimators to account for clustering within propensity score-matched pairs. Results: Among 86,365 adults discharged after an ischemic stroke between 10/2020-09/2021, 10.2% had active cancer. Based on eligibility criteria (including removal of those with known atrial fibrillation), 4,819 were assessed [median age 74 years; 48.7% female; common cancer types: 25.3% gastrointestinal, 20.3% prostate, 18.4% lung]. Anticoagulants were dispensed to 14.7% of the cohort in the week following discharge. Incidence of thromboembolic event recurrence was 37.5 per 100 person-years (66.7% ischemic stroke). Initial anticoagulation was associated with an increased risk of thromboembolism recurrence (aHR=1.42, 95% CI: 1.06-1.90). Conclusions: This large-scale real-world study demonstrates an estimated 10% of patients with ischemic stroke had active cancer, and they faced a very high 6-month incidence of recurrent thromboembolism. Anticoagulants were not commonly prescribed after discharge, suggesting that clinicians use them less commonly for stroke than for venous thromboembolism in cancer patients. The higher risk of recurrent events on anticoagulants likely reflects residual confounding by indication. Clinical trials are needed to further assess optimal antithrombotic strategies in this population.