External Validation of the HELT-E2S2 Score in Japanese Patients With Nonvalvular Atrial Fibrillation ― A Pooled Analysis of the RAFFINE and SAKURA Registries ―

Background: The HELT-E2S2 score, which assigns 1 point to Hypertension, Elderly aged 75–84 years, Low body mass index <18.5kg/m², and Type of atrial fibrillation (AF: persistent/permanent), and 2 points to Extreme Elderly aged ≥85 years and previous Stroke, has been proposed as a new risk stratification for strokes in Japanese AF patients, but has not yet undergone external validation. Methods and Results: We evaluated the prognostic performance of the HELT-E2S2 score for stroke risk stratification using 2 large-scale registries in Japanese AF patients (n=7,020). During 23,241 person-years of follow-up (mean follow-up 1,208±450 days), 287 ischemic stroke events occurred. The C-statistic using the HELT-E2S2 score was 0.661 (95% confidence interval [CI], 0.629–0.692), which was numerically higher than with the CHADS2 score (0.644, 95% CI 0.613–0.675; P=0.15 vs. HELT-E2S2) or CHA2DS2-VASc score (0.650, 95% CI, 0.619–0.680; P=0.37 vs. HELT-E2S2). In the SAKURA AF Registry, the C-statistic of the HELT-E2S2 score was consistently higher than the CHADS2 and CHA2DS2-VASc scores across all 3 types of facilities comprising university hospitals, general hospitals, and clinics. However, in the RAFFINE Study, its superiority was only observed in general hospitals. Conclusions: The HELT-E2S2 score demonstrated potential value for risk stratification, particularly in a super-aged society such as Japan. However, its superiority over the CHADS2 or CHA2DS2-VASc scores may vary across different hospital settings.