Background and aim: Fibrosis-4 (FIB-4) index is a widely used test for non-invasively assessing liver fibrosis. We aimed to investigate the association between FIB-4 index and risk of all-cause mortality in patients at high cardiovascular (CV) risk and to determine whether coexisting renal dysfunction mediates this association.
Methods and results: Single-center prospective study of 994 patients with established or suspected coronary artery disease undergoing coronary angiography, followed for a median of 44 months. Mortality data were obtained through the Italian Health Card Database. At baseline, the median FIB-4 index was greater in deceased vs. alive patients (1.71 vs. 1.38, p < 0.001) and in those with reduced eGFR than in those with normal eGFR (1.65 vs. 1.37, p < 0.001). For each unit increase in the baseline log-FIB-4 index, the risk of all-cause mortality sharply increased during the follow-up (hazard ratio [HR] 2.31, 95%CI 1.31-4.08, p = 0.004). Similarly, assuming the lowest baseline FIB-4 risk category as the reference, the risk of all-cause mortality progressively increased across the indeterminate (HR 1.82, 95%CI 1.18-2.82, p = 0.007) and the highest baseline FIB-4 risk categories (HR 2.33, 95%CI 1.37-3.97; p = 0.002). A causal mediation analysis showed that about one-third of the effect of FIB-4 index on mortality risk was mediated by reduced eGFR (32.8 %, p = 0.01).
Conclusions: Increased FIB-4 index predicts the long-term risk of all-cause mortality in patients at high CV risk, and this risk is, at least in part, mediated by reduced eGFR. Further prospective studies are needed to confirm these findings.
Keywords: All-cause mortality; Chronic kidney disease; Coronary artery disease; FIB-4; GFR.
Copyright © 2024 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.