ObjectiveLiver fibrosis (LF) is associated with a poor prognosis in patients with ischemic stroke (IS). We aimed to assess whether LF affects long-term outcomes in patients with atrial fibrillation-related stroke or such effects vary according to sex. MethodsWe conducted a multicenter prospective cohort study of Korean patients with atrial fibrillation-related IS. We calculated the fibrosis-4 (FIB-4) index, and LF degree was categorized into two groups (non-advanced vs. advanced) based on the FIB-4 index. Recurrent IS, major adverse cardiac events (MACEs), and all-cause mortality were evaluated using Cox proportional hazard model. ResultsA total of 2897 patients were included; the median age was 75 (interquartile range 68–80) years, and 51.8% were men. The median follow-up period was 16.3 months. Of these patients, 23% had advanced LF indicated by FIB-4 index. Multivariable analysis in all populations demonstrated that the FIB-4 index and advanced LF were significantly associated with MACEs and all-cause mortality but not with recurrent IS. Furthermore, a sex disparity was observed in the outcomes of the patients. A high FIB-4 index in men was a significant predictor of recurrent IS [subdistribution hazard ratio (95% confidence interval): 1.08 (1.02–1.14)]. However, the significance of advanced LF disappeared in MACEs in women and in all-cause mortality in men. ConclusionThe FIB-4 index and advanced LF indicated by FIB-4 index are independent prognostic factors for long-term outcomes in Asian patients with atrial fibrillation-related IS. However, these predictors may contribute differently to patient outcomes depending on the sex.