APRI and FIB-4 in the evaluation of liver fibrosis in chronic hepatitis C patients stratified by AST level

The aspartate aminotransferase (AST)-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) are commonly used compound surrogates for advanced fibrosis in chronic hepatitis C (CHC) patients. However, the use of APRI and FIB-4 entails a risk of overestimating the fibrosis stage due to the impact of necroinflammatory activity on transaminases. We sought to investigate the optimal cutoff values of the two compound surrogates for predicting cirrhosis stratified by AST level. This retrospective study enrolled 1716 treatment-naive CHC patients who underwent liver biopsy prior to interferon therapy from 1997-2010. Fibrosis was scored according to the modified Knodell classification. The upper limit for normal AST in our hospital is 37 IU/L. We stratified the enrolled patients into the categories of AST≤37 IU/L (N = 132), 37