Temporal patterns, incidence, and predictors of early stroke recurrence in atrial fibrillation

Introduction: Early recurrence (ER) after an acute stroke event (ASE; ischemic or hemorrhagic) in patients with atrial fibrillation (AF) presents a therapeutic challenge due to the need to balance ischemic prevention with hemorrhagic risk. This study aimed to quantify ER incidence, both ischemic and hemorrhagic, and identify its predictors using real-world data from a prospective registry. Patients and methods: Retrospective analysis of patients with AF, either known or detected within 6 months, who were admitted for a first-ever ASE to a tertiary stroke center between 2005 and 2024. ER was defined as any recurrent event within 6 months. Baseline characteristics, CHA 2 DS 2 -VASc score, CHADS-VA score, stroke severity, anticoagulation type, AF detection timing, and monitoring duration were recorded. Cox and Fine-Gray models identified independent predictors. Results: Among 1795 patients, 108 (6.0%) experienced ER. The cumulative incidence was 6.3% (95% CI 5.1–7.4), and most events occurred within the first 30 days. Independent predictors included higher CHA 2 DS 2 -VASc score (sHR = 1.252, p = 0.023), lower initial stroke severity (sHR = 0.918, p < 0.001), concomitant stroke etiologies (sHR = 2.008, p = 0.001), and AF detected within 30 days after stroke (sHR = 1.644, p = 0.026). DOAC use was protective (sHR = 0.484, p = 0.003), while VKA showed a non-significant trend (sHR = 0.637, p = 0.068). Interaction analysis showed increased recurrence risk only in non-anticoagulated patients with AF detected after stroke. These findings were consistent across sensitivity analyses restricted to ischemic stroke, incorporating time-dependent anticoagulation, or comparing CHADS-VA and CHA 2 DS 2 -VASc scores. Conclusions: ER, predominantly ischemic, occurred mainly within 30 days. Risk factors included AF detection timing, CHA 2 DS 2 -VASc score, stroke severity, concomitant causes, and anticoagulation status, supporting early risk stratification and DOAC initiation.