Lack of Concordance Between Empirical Scores and Physician Assessments of Stroke and Bleeding Risk in Atrial Fibrillation: Results From the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) Registry

Study Questions:

How closely does physician assessment of stroke and bleeding risk coincide with formal risk scores in patients with atrial fibrillation (AF)?


The data for this study were obtained from a multicenter registry of 10,094 outpatients with AF (ORBIT-AF Registry). CHADS2 and ATRIA scores were calculated. CHADS2 scores of 0, 1, and ≥2 were categorized as low, intermediate, and high risk for stroke, respectively. ATRIA scores of 0-3, 4, and ≥5 were categorized as low, intermediate, and high risk of bleeding on anticoagulation therapy. Physicians were asked to subjectively classify patients into low-risk (<3%), intermediate-risk (3-6%), or high-risk (>6%) subgroups for stroke and bleeding complications.


The CHADS2 score identified 72% of patients as high-risk for stroke, compared to only 16% based on physician assessment. The ATRIA score indicated a high risk of bleeding in 17% of patients, compared to 7% based on physician assessment. Compared to the CHADS2 score, physician-assigned stroke risk was less influenced by hypertension, heart failure, and diabetes. Approximately 80% of patients deemed to be at high risk for stroke based either on the CHADS2 score or physician assessment were treated with an anticoagulant.


The authors concluded that physicians often underestimate the risk of stroke in patients with AF.


Several studies have demonstrated the underutilization of anticoagulation therapy in high-risk patients with AF. The introduction of new anticoagulants that eliminate many of the problems associated with warfarin has had little impact on the underutilization. This study indicates that a major reason for underutilization of anticoagulants could be a failure of physicians to accurately identify high-risk patients.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Prevention, Anticoagulation Management and Atrial Fibrillation, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Hypertension

Keywords: Stroke, Warfarin, Heart Failure, Atrial Fibrillation, Hypertension, Hemorrhage, Diabetes Mellitus, ACC Annual Scientific Session

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