Abstract 12274: Comparison of Clinical Risk Stratification for Predicting Stroke and Thromboembolism in Atrial Fibrillation
Background Several accepted algorithms exist to characterize the risk of thromboembolism in patients with atrial fibrillation. The CHA2DS2-VASc score has recently been adopted as part of the European guidelines, and we performed a comparative analysis to assess the predictive value of 9 such schemes.
Methods In a longitudinal community-based cohort study from Olmsted County, MN, 2854 residents with atrial fibrillation were followed for 4.4 ± 3.6 years from 1990 through 2004. Risk factors were identified using a diagnostic index integrated with the electronic medical record. Thromboembolism (TE) and cardiovascular (CV) event data were collected in all patients, and each scheme was stratified into low, intermediate, and high risk categories and applied to our cohort. The hazard ratio and concordance c-statistic was calculated for each risk scheme.
Results We identified 366 validated TE events in our cohort. Multivariate analysis identified age > 75 years (OR 1.85, p = 0.0005), female gender (OR 1.39, p = 0.0426), history of hypertension (OR 4.47, p = 0.0004), and history of CHF (OR 1.68, p = 0.019) to be significant predictors of clinical TE. The performance of all risk schemes were evaluated in anticipating TE events, with hazard ratios and concordance c-statistics as follows: Low risk patients in the ACC/AHA/ESC, 8th ACCP, and NICE schemes had < 1% TE event rate. Increased scores in the CHADS2-classical (HR 2.282, p < 0.0001) and CHADS2-revised (HR 2.588, p < 0.0001) schemes were associated with higher risk for CV events.
Conclusions A direct comparison of old and new risk schemes reveals no significant difference in risk stratification accuracy. Accurate prediction of low risk patients is valuable in determining those unlikely to benefit from oral anticoagulation therapy. Interestingly, some schemes appear to be useful in identification of CV event risk.
- © 2012 by American Heart Association, Inc.