Validation and comparison of simple noninvasive models for the prediction of liver fibrosis in chronic hepatitis C

Introduction. Although it is standard procedure in the evaluation of liver diseases, biopsy is an invasive method subject to sampling error and intra or inter-observer variability. Thus, surrogate markers of liver fibrosis have been proposed, with variable availability and accuracy. Aim. Validate and compare the performance of APRI and FIB-4 as predictors of liver fibrosis in HCV patients. Material and methods. Cross-sectional study including patients with HCV-RNA (+) who underwent liver biopsy. Significant fibrosis was defined as METAVIR stage >= 2. The diagnostic performance of the models in predicting significant fibrosis were evaluated and compared by ROC curves. Results. The study included 119 patients, mean age 43.7 +/- 10.6 years and 62% males. Significant fibrosis was identified in 41 patients. The AUROCs observed were: APRI = 0.793 +/- 0.047, FIB-4 = 0.811 +/- 0.045 and AST/ALT = 0.661 +/- 0.055 (P = 0.054 for APRI vs. AST/ALT, and P = 0.014 for FIB-4 vs. AST/ALT). Considering classic cutoffs, the PPV and NPV for APRI and FIB-4 were, respectively, 77% and 92% and 83% and 81%. Thirteen (19%) patients were misdiagnosed by APRI and 16 (18%) by FIB-4. By restricting the indication of liver biopsy to patients with intermediate values, it could have been correctly avoided in 47% and 63% of the patients with APRI and FIB-4, respectively. Conclusion. The models APRI and FIB-4 were superior to AST/ALT ratio in the diagnosis of significant fibrosis in chronic HCV infection. Even though the overall performance of APRI and FIB-4 was similar, a higher proportion of patients may be correctly classified by FIB-4.