Predicting Bleeding in Stroke Patients With Atrial Fibrillation

Study Questions:

How well do risk models of major bleeding for patients with atrial fibrillation on anticoagulation perform in patients with a previous transient ischemic attack (TIA) or stroke?


The authors evaluated five bleeding risk prediction models: HEMORR2HAGES, Shireman, HAS-BLED, ATRIA, and ORBIT. To validate these models, the authors used a subset of atrial fibrillation subjects (n = 3,623) from the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial who had had a previous TIA or stroke and were randomized to either dabigatran or warfarin. During 6,922 person-years of follow-up, there were 266 major bleeding events. Model performance was assessed with C-statistics. (A C-statistic is equal to the area under a receiver operating characteristic [ROC] curve and ranges from 0 to 1.0. A C-statistic of 0.5 suggests that a model is no better than random chance at predicting risk. A C-statistic of ≥0.8 is generally considered a strong model.) In addition, the authors looked at the 1-year net benefit of warfarin for patients in the low, moderate, and high ORBIT bleeding risk categories by comparing the risk reduction in recurrent ischemic stroke to the increased risk of major bleeding.


For patients with atrial fibrillation and a previous TIA or stroke treated with either dabigatran or warfarin, C-statistics for the five bleeding prediction models ranged from 0.62 to 0.67, suggesting moderate performance for each. This observed performance is similar to the performance of these five models in anticoagulated atrial fibrillation patients in general. The benefit of warfarin in ischemic stroke prevention outweighed the bleeding risk in all ORBIT bleeding risk categories.


Performance of five bleeding risk prediction models for patients with atrial fibrillation on anticoagulation with a previous TIA or stroke is comparable to the performance of these models in patients with atrial fibrillation on anticoagulation without a previous TIA or stroke.


These prediction models may be of limited utility given that patients with atrial fibrillation and previous TIA/stroke showed a net benefit of anticoagulation in all bleeding risk categories, including the highest risk category.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Heart Atria, Hemorrhage, Ischemia, Ischemic Attack, Transient, Primary Prevention, Risk Factors, Stroke, Vascular Diseases, Warfarin

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