Incidence and prediction of ischemic stroke among atrial fibrillation patients with end-stage renal disease requiring dialysis

Background Renal dysfunction is a significant risk factor for ischemic stroke in atrial fibrillation (AF). However, the incidence of ischemic stroke and how to predict its occurrence among AF patients with end-stage renal disease (ESRD) are unclear. Objective The purpose of this study was to compare the CHADS₂ and CHA₂DS₂-VASc scores for stroke risk stratification in AF patients with ESRD. Methods A total of 10,999 AF patients with ESRD undergoing renal replacement therapy who were not receiving oral anticoagulants or antiplatelet agents were identified from Taiwan's National Health Insurance Research Database. The study end-point was occurrence of ischemic stroke. Results The median (interquartile) CHADS₂ and CHA₂DS₂-VASc scores for the study cohort were 3 (2-5) and 5 (4-7), respectively. During follow-up, 1217 patients (11.7%) experienced ischemic stroke, with an incidence rate of 6.9 per 100 person-years. In Cox regression models, the CHADS₂ and CHA₂DS₂-VASc scores both were significant predictors of ischemic stroke. C-indexes for CHADS₂ and CHA₂DS₂-VASc were 0.608 and 0.682, respectively (P <.001). CHA₂DS₂-VASc improved the net reclassification index by 4.8% compared with CHADS₂ (P <.0001). Among 1409 patients with a CHADS₂ score of 0 or 1, the CHA₂DS₂-VASc score ranged from 1 to 4, with event rates ranging from 2.1 to 4.7 per 100 person-years. Conclusion The CHA₂DS₂-VASc score was useful in predicting ischemic stroke in AF patients with ESRD undergoing dialysis and was superior to the CHADS₂ score. The net clinical benefit balancing stroke reduction against major bleeding with anticoagulation in these high-risk patients remains to be defined.