Comparison of the CHADS(2), CHA(2)DS(2)-VASc and R(2)CHADS(2) Scores in Japanese Patients with Non-valvular Paroxysmal Atrial Fibrillation Not Receiving Anticoagulation Therapy

OBJECTIVE: It remains unclear whether the CHADS(2), CHA(2)DS(2)-VASc, or R(2)CHADS(2) score is the most useful for the risk stratification of ischemic stroke/systemic thromboembolism (IS/SE) in Japanese patients with paroxysmal non-valvular atrial fibrillation (PNVAF). METHODS: We investigated the incidence of IS/SE on the basis of the CHADS(2), CHA(2)DS(2)-VASc, and R(2)CHADS(2) scores in 332 consecutive PNVAF patients (224 men, mean age: 65±13 years) who had not been administered anticoagulation therapy but who were administered antiarrhythmic drug therapy to maintain sinus rhythm between August 1995 and July 2008 before the 2008 Japanese Circulation Society guideline was issued (mean follow-up period: 53±35 months). RESULTS: The annual rates of IS/SE without underlying antiarrhythmic drug therapy are shown in the table included in this article. Higher CHADS(2), CHA(2)DS(2)-VASc, and R(2)CHADS(2) scores were associated with greater annual rates of IS/SE (p<0.001). In a multivariate logistic regression analysis adjusted for potentially confounding variables, the CHADS(2) scores [odds ratio (OR): 4.74, 95% confidence interval (CI): 2.80-8.00, p<0.001], CHA(2)DS(2)-VASc scores (OR: 4.15, 95% CI: 2.57-6.71, p<0.001), and R(2)CHADS(2) scores (OR: 1.94, 95% CI: 1.48-2.53, p<0.001) were significant independent predictors of IS/SE. The area under the receiver-operator characteristic curve for predicting IS/SE was 0.89 for CHA(2)DS(2)-VASc scores, 0.87 for CHADS(2) scores, and 0.85 for R(2)CHADS(2) scores (all, p<0.001), with no significant difference among the three scores. CONCLUSION: In Japanese patients with PNVAF, the CHADS(2), CHA(2)DS(2)-VASc, and R(2)CHADS(2) scores are all useful for the risk stratification of IS/SE cases.