Incremental value of blood-based markers of liver fibrosis in cardiovascular risk stratification.

AIMS Non-alcoholic fatty liver disease (NAFLD) with advanced liver fibrosis is associated with cardiovascular disease (CVD). To examine if markers of vascular injury mediate the link between liver fibrosis non-invasive tests (LFNITs) and CVD events, and to compare the incremental predictive value of LFNITs over established CVD risk scores. METHODS Consecutively recruited individuals (n=1,692) with or without clinically overt coronary artery disease (CAD) from the Athens Cardiometabolic Cohort, were analysed. Fibrosis-4 index (FIB-4), NAFLD Fibrosis score (NFS), and BARD score were evaluated for direct and indirect associations with indices of subclinical arterial injury including carotid maximal wall thickness (maxWT) and pulse wave velocity (PWV) and with a composite of major adverse cardiovascular events (MACE) that consisted of cardiac death, acute myocardial infarction, or coronary revascularization (39-month median follow-up). RESULTS FIB-4 was the only LFNIT which consistently associated with multiple markers of vascular injury, irrespective of CAD presence and after controlling for traditional risk factors, surrogates of insulin resistance or obesity (adjusted p<0.05 for all). FIB-4 also independently associated with CAD presence (adjusted OR 6.55 (3.48-12.3), p<0.001). Increased FIB-4>2.67 was incrementally associated with increased risk for MACE (OR (95% CI) 2.00(1.12, 3.55), deltaAUC (95% CI) 0.014(0.002-0.026)). These associations were mediated by maxWT rather than PWV. Only FIB-4 (>3.25) was independently and incrementally associated with all-cause mortality (adjusted p<0.05). CONCLUSIONS In a cardio-metabolically diverse population, the incremental associations of LFNITs with CVD outcomes were mediated by atherosclerotic burden rather than arterial stiffening. FIB-4 consistently demonstrated associations with all study endpoints. These findings provide mechanistic insights and support the clinical applicability of FIB-4 in CVD prevention.