Liver fibrosis in nonalcoholic fatty liver disease patients: noninvasive evaluation and correlation with cardiovascular disease and mortality

Liver fibrosis is critical for liver-related outcomes and mortality in chronic liver disease, irrespective of etiology, including nonalcoholic fatty liver disease (NAFLD). NAFLD has been viewed as an independent correlate of cardiovascular risk. This review article briefly describes the cellular and molecular pathomechanisms underlying hepatic fibrosis. We then address noninvasive assessment of liver fibrosis. Finally, we discuss published evidence supporting fibrosis biomarkers’ role in assessing cardiovascular risk among patients with NAFLD. While histological assessment is the diagnostic standard of hepatic fibrosis, we specifically address noninvasive techniques, including equations based on anthropometric parameters, laboratory indices, and elastometry obtained with imaging techniques. The former group includes AST: ALT ratio, the Forns Index, the AST-to-platelet ratio index score, BARD (BMI, AAR, Diabetes) score, the fibrosis-4 index (FIB-4), the NAFLD fibrosis score, the gamma-glutamyl transferase-to-platelet ratio, and the Hepamet fibrosis score. The latter comprises elastographic techniques associated with ultrasonography or magnetic resonance. Our literature review identified numerous studies demonstrating that biomarkers of fibrosis (the most common being FIB-4) and elastographic techniques predict overall mortality and major cardiovascular events among NAFLD patients. The mechanisms accounting for this association are briefly reviewed. In addition to assessing hepatic fibrosis at baseline, during follow-up, and after therapeutic interventions in NAFLD patients, noninvasive assessment of hepatic fibrosis may predict cardiovascular events and overall mortality in these patients.