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

Mar 29, 2014
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Authors:
Steinberg BA, Kim S, Thomas L, et al., on behalf of the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) Investigators and Patients.
Citation:
Circulation 2014;Mar 29:[Epub ahead of print].
Summary By:
Fred Morady, MD, FACC

Study Questions:

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

Methods:

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.

Results:

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.

Conclusions:

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

Perspective:

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.

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


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