The value of the CHA(2)DS(2)-VASc score for refining stroke risk stratification in patients with atrial fibrillation with a CHADS(2) score 0-1: A nationwide cohort study

作者：Olesen, Jonas Bjerring^*; Torp-Pedersen, Christian; Hansen, Morten Lock; Lip, Gregory Y. H.

来源：Thrombosis and Haemostasis, 2012, 107(6): 1172-1179.

DOI：10.1160/TH12-03-0175

• Atrial fibrillation
• epidemiology
• stroke
• risk score

North American and European guidelines on atrial fibrillation (AF) are conflicting regarding the classification of patients at low/intermediate risk of stroke. We aimed to investigate if the CHA(2)DS(2)-VASc score improved risk stratification of AF patients with a CHADS(2) score of 0-1. Using individual-level-linkage of nationwide Danish registries 1997-2008, we identified patients discharged with AF having a CHADS(2) score of 0-1 and not treated with vitamin K antagonist or heparin. In patients with a CHADS(2) score of 0, 1, and 0-1, rates of stroke/thromboembolism were determined according to CHA(2)DS(2)-VASc score, and the risk associated with increasing CHA(2)DS(2)-VASc score was estimated in Cox regression models adjusted for year of inclusion and antiplatelet therapy. The value of adding the extra CHA(2)DS(2)-VASc risk factors to the CHADS(2) score was evaluated by c-statistics, Net Reclassification Improvement (NRI) and Integrated Discrimination Improvement (IDI). We included 47,576 patients with a CHADS(2) score of 0-1, from these 7,536 (15.8%) were CHA(2)DS(2)-VASc score=0, 10,062 (21.2%) were CHA(2)DS(2)-VASc score=1, 14,310 (30.1%) were CHA(2)DS(2)-VASc score=2, 14,188 (29.8%) were CHA(2)DS(2)-VASc score=3, and 1,480 (3.1%) were CHA(2)DS(2)-VASc score=4. Of the cohort with a CHADS(2) score of 0-1, the stroke/thromboembolism rate per 100 person-years increased with increasing CHA(2)DS(2)-VASc score (95% confidence interval): 0.84 (0.65-1.08), 1.79 (1.53-2.09), 3.67 (3.34-4.03), 5.75 (5.33-6.21), and 8.18 (6.68-10.02) at one year follow-up with CHA(2)DS(2)-VASc scores of 0, 1, 2, 3, and 4, respectively. Patients with a CHADS(2) score=0 were not all 'low risk', with one-year event rates ranging from 0.84 (CHA(2)DS(2)-VASc score=0) to 3.2 (CHA(2)DS(2)-VASc score=3). Results from Cox regression analyses, NRI, and IDI confirmed the improved predictive ability of the CHA(2)DS(2)-VASc score in the AF patients who have a CHADS(2) score of 0-1. In conclusion, the CHA(2)DS(2)-VASc provides critical information on risk of stroke in AF patients with a CHADS(2) score of 0-1 that can aid a decision of using anticoagulation. Even in patients categorised as 'low risk' using a CHADS(2) score=0, the CHA(2)DS(2)-VASc score significantly improved the predictive value of the CHADS(2) score alone and a CHA(2)DS(2)-VASc score=0 could clearly identify 'truly low risk' subjects. Use of the CHA(2)DS(2)-VASc score would significantly improve classification of AF patients at low and intermediate risk of stroke, compared to the commonly used CHADS(2) score.

• 出版日期2012-6