A simple approach to noninvasively identifying significant fibrosis in chronic hepatitis C patients in clinical practice

Background: Identification of the presence of significant fibrosis is an important part of the diagnostic work-up of patients with chronic hepatitis C (CHC). Aim: To evaluate the performance of the aspartate to alanine aminotransferase ratio (AST/ALT ratio) and platelet count in reducing the number of liver biopsies and diagnosing the presence/absence of significant fibrosis in a large cohort of patients with CHC seen at 2 tertiary referral centers. Methods: Liver biopsies of 409 patients with CHC were evaluated. Staging was carried out by means of the Ishak and METAVIR scores in the Italian and US series, respectively. Prevalence of significant fibrosis was 43%. Receiver operating characteristic curves were used to identify AST/ALT ratio and platelet count cutoffs with the highest accuracy for the diagnosis of significant fibrosis. These cutoffs were used to devise a diagnostic algorithm for reducing the number of liver biopsies and diagnosing/ruling out significant fibrosis. Results: AST/ALT ratios increased and platelet counts decreased as liver fibrosis worsened. Both AST/ALT ratio (c-index = 0.747) and platelet count (c-index = 0.733) had high accuracy for the diagnosis of significant fibrosis. The use of AST/ALT ratio and platelet count cutoffs in a diagnostic algorithm would have avoided liver biopsy in 68.9% of the patients and would have correctly identified the absence/presence of significant fibrosis in 80.5% of these cases. Conclusions: In clinical practice, the use of simple, reproducible, and inexpensive parameters such as the AST/ALT ratio and platelet count can reduce the need for liver biopsy in a substantial proportion of patients with CHC.