Clinical Decisionmaking

A new classification scheme quantifies the risk of hemorrhage among atrial fibrillation patients taking anticoagulants

Warfarin and other anticoagulant medications can prevent stroke, heart attack, and venous thromboembolism (deep blood clot in the veins, usually the legs). However, they often cause hemorrhaging, which makes physicians reluctant to prescribe anticoagulants for elderly patients with atrial fibrillation (AF, irregular heart beat) who are at increased risk of stroke. A new clinical classification scheme can quantify the risk of hemorrhage and aid in the management of anticoagulant therapy for AF patients, concludes a new study. Brian F. Gage, M.D., M.Sc., of the Washington University School of Medicine, and colleagues combined bleeding risk factors from three existing classification schemes into a new scheme, HEMORR₂HAGES.

They compared the accuracy of all 4 schemes in predicting hemorrhage among 3,791 Medicare beneficiaries with AF from 7 States, of whom 162 were hospitalized for hemorrhage. The researchers scored HEMORR₂HAGES by adding 2 points for a prior bleed and 1 point for each of the other risk factors: hepatic or renal disease, ethanol abuse, malignancy, older age (more than 75 years), reduced platelet count or function, uncontrolled hypertension, anemia, genetic factors, excessive fall risk, and stroke. With each additional point, the rate of bleeding per 100 patient-years of warfarin increased: 1.9 for 0 points, 2.5 for 1, 5.3 for 2, 8.4 for 3, 10.4 for 4, and 12.3 for 5 or more points.

HEMORR₂HAGES better predicted hemorrhaging among AF patients prescribed warfarin than older bleed prediction schemes, but they all quantified the rate of hemorrhage in this group. High-risk patients identified by any of the schemes had a much greater hemorrhage rate (7.5-15.3 per 100 patient-years) than that of low-risk patients (1.1-2.9), validating the ability of the schemes to risk-stratify elderly patients with AF. The researchers suggest that clinicians could use HEMORR₂HAGES to help manage patients for whom more aggressive anticoagulant regimens can only be justified when they are unlikely to cause bleeding. The study was supported in part by the Agency for Healthcare Research and Quality (HS10133).

More details are in "Clinical classification schemes for predicting hemorrhage: Results from the national registry of atrial fibrillation (NRAF)," by Dr. Gage, Yan Yan, M.D., Ph.D., Paul E. Milligan, R.Ph., and others, in the March 2006 American Heart Journal 151, pp. 713-719.

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