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16-11-2011 | Cardiology | Article

High CHADS2 also predicts bleeding, mortality


Free abstract

MedWire News: The CHADS2 score predicts the risk for bleeding, intracranial bleeding, and mortality, as well as stroke, in patients with atrial fibrillation (AF), shows an analysis of the RE-LY trial.

The RE-LY (Randomized Evaluation of Long-term Anticoagulation Therapy) trial was a head-to-head comparison of two doses of dabigatran (110 and 150 mg twice daily) with dose-adjusted warfarin in 18,112 patients with AF.

CHADS2 assesses stroke or systemic embolism risk in AF patients based on the presence of five factors: congestive heart failure; hypertension; age of 75 years or older; diabetes; and history of stroke. In the RE-LY population, annual stroke and embolism rates rose from 0.93% among patients with a CHADS2 score of 0-1, to 1.22% and 2.44% among those with scores of 2 and 3-6, respectively.

However, annual rates of major bleeding also rose significantly with increasing CHADS2 score, at 2.26%, 3.11%, and 4.42% for scores of 0-1, 2, and 3-6, respectively. The same was true for other important outcomes, with corresponding intracranial bleeding rates of 0.31%, 0.40%, and 0.61%; vascular death rates of 1.35%, 2.39%, and 3.68%; and total mortality rates of 2.30%, 3.88%, and 5.35%.

The strong relationship between CHADS2 score and outcomes held true regardless of whether patients were receiving warfarin or dabigatran. Intracranial bleeding was significantly less common among patients taking dabigatran than warfarin, however, and stroke or embolism was less frequent among those taking dabigatran 150 mg than the 110 mg dose or warfarin, as previously reported. The differences between the dabigatran and warfarin groups were consistent across subgroups of CHADS2 scores.

The study is published in the Annals of Internal Medicine. In an accompanying editorial, Rebecca Beyth (University of Florida, Gainesville, USA) and C Seth Landefeld (University of California, San Francisco, USA) write that the findings "extend our knowledge in important ways."

They point out that patients with CHADS2 scores of 3 or more have the most to gain from anticoagulant therapy, but also the most to lose. In addition, most of these patients are aged 75 years or older, "the population in whom dabigatran was associated with a higher rate of major bleeding than warfarin."

The editorialists conclude that, as long as international normalized ratio can be tightly controlled, "warfarin may remain the preferred anticoagulant therapy, especially in patients aged 75 years or older or with CHADS2 scores of 3 or higher."

By Eleanor McDermid

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