Comparing risk stratification for thromboembolism in atrial fibrillation

January 01, 0001

Comparing risk stratification for thromboembolism in atrial fibrillation

These Danish and UK researchers evaluated the components of the CHADS2 (Congestive heart failure, Hypertension, Age, Diabetes, history of Stroke) score and the CHA2DS2-VASc (CHA2DS2-Vascular disease, Age, Sex category) score and determined the two schemes abilities to determine risk of thromboembolism. They did so via a registry based cohort study of all patients admitted to hospitals in Denmark with atrial fibrillation and not taking vitamin K antagonists

The researchers found: "Of 121?280 patients with non-valvular atrial fibrillation, 73?538 (60.6%) fulfilled the study inclusion criteria. In patients at "low risk" (score=0), the rate of thromboembolism per 100 person years was 1.67 with CHADS2 and 0.78 with CHA2DS2-VASc at one year’s follow-up. In patients at "intermediate risk" (score=1), this rate was 4.75 with CHADS2 and 2.01 with CHA2DS2-VASc. The rate of thromboembolism depended on the individual risk factors composing the scores, and both schemes underestimated the risk associated with previous thromboembolic events. When patients were categorised into low, intermediate, and high risk groups, C statistics at 10 years’ follow-up were 0.812 with CHADS2 and 0.888 with CHA2DS2-VASc."

The researchers concluded: "The risk associated with a specific risk stratification score depended on the risk factors composing the score. CHA2DS2-VASc performed better than CHADS2 in predicting patients at high risk, and those categorised as low risk by CHA2DS2-VASc were truly at low risk for thromboembolism."

This study finds the CHA2DS2-VASc scheme may be a better than CHADS2 predictor of risk of thromboembolism in patients with atrial fibrillation

For the full abstract, click here.

BMJ 342:d124, 31 January 2011
© 2011 BMJ Publishing Group Ltd.
Validation of risk stratification schemes for predicting stroke and thromboembolism in patients with atrial fibrillation: nationwide cohort study. Jonas Bjerring Olesen, Gregory Y H Lip, Morten Lock Hansen, et al. Correspondence to J Olesen: [email protected]

Category: K. Circulatory, N. Neurological. Keywords: atrial fibrillation, thromboembolism, risk stratification, CHADS2, CHA2DS2-VASc, cohort study, journal watch.
Synopsis edited by Dr Paul Schaefer, Toledo, Ohio. Posted on Global Family Doctor 15 February 2011

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