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CHA Background and Purpose- Despite modest predictive ability for ischemic stroke (IS), the CHA2DS2-VASc score is widely used for stroke prediction in atrial fibrillation. Among patients with atrial fibrillation, we aimed to (1) compare the IS or transient ischemic attack (TIA) incidence by CHA2DS2-VASc in blacks and Hispanics versus whites; (2) compare predictive ability of CHA2DS2-VASc score for IS or TIA in blacks and Hispanics versus whites; and (3) determine improvement in predictive ability of CHA2DS2-VASc score from addition of race/ethnicity. Methods- Using data from Optum Clinformatics, a large administrative claims database, we analyzed patients with atrial fibrillation enrolled in commercial and Medicare Advantage health plans from 2009 to 2015. We computed IS or TIA incidence rates, improvement in C statistic, continuous and categorical net reclassification improvement, and relative integrated discrimination improvement from addition of race/ethnicity to CHA2DS2-VASc. Results- A total of 267 419 patients (mean age, 73.1 [SD, 12.3] years; 46.6% women; 84.2% white, 8.5% black, 7.3% Hispanic) were studied. After a mean follow-up of 22 months, there were 6202 IS or TIA events. IS or TIA incidence rates were higher in blacks than Hispanics or whites (1.65, 1.40, and 1.22 cases per 100 person-years, respectively) and increased with higher CHA2DS2-VASc, with no race/ethnicity-based differences (P for interaction=0.17). The CHA2DS2-VASc and CHA2DS2-VASc+race/ethnicity C statistic (95% CI) were 0.679 (0.670-0.686) and 0.679 (0.671-0.688). The CHA2DS2-VASc C statistic in the 3 groups were comparable. With addition of race/ethnicity, the categorical net reclassification improvement, continuous net reclassification improvement, and relative integrated discrimination improvement were -0.045 (95% CI, -0.067 to -0.025), 0.045 (95% CI, 0.025-0.068), and 0.016 (95% CI, 0.014-0.018). Conclusions- The predictive ability of CHA2DS2-VASc for IS or TIA in atrial fibrillation is comparable among whites, blacks, and Hispanics; hence, it can be used in the latter 2 groups. Addition of race/ethnicity to the CHA2DS2-VASc does not improve its predictive ability.

CHA BACKGROUND AND PURPOSE: As the threshold of stroke risk for initiating oral anticoagulants is lowered after the introduction of the nonvitamin K antagonist oral anticoagulants, the focus of stroke prevention in patients with nonvalvular atrial fibrillation has shifted away from predicting high-risk patients toward initially identifying patients with a truly low risk of ischemic stroke, who do not need antithrombotic therapy. We tested the predictive ability of the congestive heart failure, hypertension, age ≥75, diabetes mellitus, prior stroke or transient ischemic attack (doubled; CHADS2), congestive heart failure, hypertension, age ≥75 (doubled), diabetes mellitus, prior stroke or transient ischemic attack (doubled), vascular disease, age 65 to 74, female (CHA2DS2-VASc), and Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) risk stratification schemes in oral anticoagulants naive patients with atrial fibrillation in a Korean nationwide sample cohort. METHODS: From January 2002 to December 2008, a total of 5855 oral anticoagulant naive patients with nonvalvular atrial fibrillation aged ≥20 years were enrolled from Korea National Health Insurance Service-Sample Cohort database and were followed-up until December 2013. RESULTS: At baseline, the proportions categorized as low risk using CHADS2, CHA2DS2-VASc, and ATRIA risk stratification schemes were 1049 (17.9%), 860 (14.7%), and 3280 (56.0%), respectively. During follow-up, the low-risk category using CHADS2, CHA2DS2-VASc, and ATRIA scores was retained in 811 (13.9%), 667 (11.4%), and 2729 (46.6%) patients, respectively. Rates of ischemic stroke (100 person-years) in the low risk categories of CHADS2, CHA2DS2-VASc, and ATRIA scores were 0.42, 0.26, and 1.43, respectively. CHA2DS2-VASc had the best sensitivity (98.8% versus 85.7% in CHADS2 and 74.8% in ATRIA) and negative predictive value (98.8% versus 95.3% for CHADS2 and 93.7% for ATRIA) for the prediction of stroke incidence and was best for the prediction of the absence of ischemic stroke during 5 years of follow-up (odds ratio, 16.4 [95% confidence interval, 8.8-30.8]). CONCLUSIONS: The CHA2DS2-VASc score shows good performance in defining truly low-risk Asian patients with atrial fibrillation for stroke compared with CHADS2 and ATRIA scores.

CHA BACKGROUND AND PURPOSE: The CHA2DS2-VASc stroke score (congestive heart failure, hypertension, age ≥75 (doubled), diabetes mellitus, prior stroke or transient ischemic attack (doubled), vascular disease, age 65-74, female) is used in most guidelines for risk stratification in atrial fibrillation (AF), but most data for this score have been derived in Western populations. Ethnic differences in stroke risk may be present. Our objective was to investigate risk factors for stroke in AF and application of the CHA2DS2-VASc score in an Asian AF population from Korea. METHODS: A total of 5855 oral anticoagulant-naive nonvalvular AF patients aged ≥20 years were enrolled from Korea National Health Insurance Service Sample cohort from 2002 to 2008 and were followed up until December 2013. RESULTS: The incidence rates (per 100 person-years) of ischemic stroke were 3.32 in the total population, being 0.23 in low-risk (CHA2DS2-VASc score 0 [male] or 1 [female]) and 4.59 in high-risk patients (CHA2DS2-VASc ≥2). Incidence rates of ischemic stroke or the composite thromboembolism end point showed a clear increase with increasing CHA2DS2-VASc score. On multivariable analysis, significant associations between CHA2DS2-VASc risk factors and ischemic stroke were observed; however, the significance of vascular disease or diabetes mellitus was attenuated after multivariate adjustment, and female sex (hazard ratio, 0.73; 95% confidence interval, 0.64-0.84) had a lower risk of ischemic stroke than males. Patients who were categorized as low risk consistently had an event rate <1% per year. CONCLUSIONS: The performance of CHA2DS2-VASc score in Asians is comparable with that in Western populations. The score shows good performance in defining the truly-low-risk AF patients for stroke/thromboembolism.