Abstract 34: Liver Fibrosis, Apolipoprotein E, And Hemorrhagic Stroke Risk: A Cohort Analysis

Abstract

Introduction: Cirrhosis is associated with an increased risk of hemorrhagic stroke (HS). Liver fibrosis, typically a silent condition, is antecedent to cirrhosis. We hypothesized that liver fibrosis is associated with an increased risk of HS. Further, because apolipoprotein E2 (ApoE2) and E4 (ApoE4) are associated with HS, and because liver-derived peripheral ApoE4 may disrupt endothelial integrity, we evaluated for effect modification by these isoforms. Methods: We performed a cohort analysis using the UK Biobank Study, which prospectively enrolled adults in 2007, with continuous follow-up. We excluded participants with prevalent HS or thrombocytopenia. Liver fibrosis was defined using the validated Fibrosis-4 score. The primary outcome, incident HS (intracerebral or subarachnoid hemorrhage), was captured in UK Biobank based on hospitalization and death registry data. We used Cox proportional hazards models to evaluate the association of liver fibrosis with HS while adjusting for HS risk factors (demographics, systolic blood pressure, hemoglobin A1c, total cholesterol, BMI, tobacco and alcohol use, antithrombotic use). Effect modification by ApoE2 and ApoE4 were evaluated using interaction terms and stratified analyses. Results: Among 453,251 included participants, the mean age was 57 years and 54% were women. Approximately 2% had liver fibrosis, 16% used antithrombotic agents, 29% were ApoE4 carriers, and 15% were ApoE2 carriers. In adjusted Cox models, liver fibrosis was associated with an increased risk of HS (HR, 2.17; 95% CI, 1.51-3.12) (Figure). This relationship appeared stronger in ApoE4 homozygotes (HR, 8.27; 95% CI, 2.30-29.73) than in others (HR, 2.18; 95% CI, 1.47-3.24) (P=0.05, interaction). ApoE4 carrier status, ApoE2 carrier status, and ApoE2 homozygosity did not modify this relationship (P>0.20, interactions). Conclusions: Liver fibrosis was associated with an increased risk of HS, possibly more so in ApoE4 homozygous persons.