Li YG, et al. - Researchers used an internal derivation cohort (n=471,446) and an external cohort (n=451,199) to develop a simple clinical risk score to predict incident atrial fibrillation (AF) in Asian individuals. Patients with structural heart disease (SHD) were excluded from analysis. SHD, heart failure (HF), age ≥ 75 years, coronary artery disease (CAD), hyperthyroidism, COPD, and hypertension were found to be associated with incident AF in the internal cohort. Combining the remaining predictors, a new simple C₂HEST score was developed: C2: CAD/COPD (1 point each); H: hypertension; E: elderly (age ≥ 75 years, doubled); S: systolic HF (doubled); and T: thyroid disease (hyperthyroidism). The C₂HEST score displayed good discrimination and good calibration. An area under the curve (AUC) of 0.75 was generated when the score was internally validated. Its external application gave an AUC of 0.65. It offered a better prediction of incident AF in both cohorts vs CHADS₂ and CHA₂DS₂VASc scores. Overall, the C₂HEST score was validated to clinically assess the individual risk of developing AF in the Asian population without SHD.