Chua SK, Hsieh FI, Hu CJ, et al. - In a nationwide hospital-based prospective study, 3,775 embolic stroke of undetermined source (ESUS) patients were enrolled to determine the usefulness of advanced renal dysfunction, defined as estimated glomerular filtration rate < 30mL/min per 1.73 m² or patients under dialysis, and its addition to the CHA₂DS₂‐VASc score in improving predictive accuracy. After adjusting for confounding factors and CHA₂DS₂‐VASc score, advanced renal dysfunction exhibited significant associations with all‐cause mortality and poor functional outcome at third‐ and sixth‐month post‐stroke. Findings suggested that advanced renal dysfunction has been significantly correlated with clinical and functional outcomes in ESUS patients and can improve the prognostic impact of the CHA₂DS₂‐VASc score.