Individual Treatment Effect Estimation of 2 Doses of Dabigatran on Stroke and Major Bleeding in Atrial Fibrillation: Results from the RE-LY Trial

Background: We aimed to estimate absolute benefit and harm from treatment with dabigatran in individual patients with atrial fibrillation, and to select the optimal dose for each individual. Methods: We derived and validated a prediction model for ischemic stroke/ systemic embolism (SE) and major bleeding in patients with atrial fibrillation from the 3 treatment arms of the randomized evaluation of long-term anticoagulation therapy (RE-LY) trial (n=11,955 in derivation cohort, n=6,158 in validation cohort). Readily available patient characteristics were included in Fine & Gray competing risk models (sex, age, smoking, antiplatelet drugs, prior vascular disease, diabetes, blood pressure, eGFR, and hemoglobin). Five-year risks for ischemic stroke/SE and major bleeding were estimated without anticoagulation therapy, and compared with high and low dose dabigatran. Results: Model calibration was good, and discrimination was adequate with a c-statistic of 0.65 (95%CI 0.62-0.70) for ischemic stroke/SE and ...