Serum aminotransferase levels and platelet counts as predictors of degree of fibrosis in chronic hepatitis C virus infection

OBJECTIVE: In patients with chronic hepatitis C virus (HCV) infection, liver fibrosis stage is a prognostic factor for therapy outcome. So far, a liver biopsy is necessary to determine disease stage accurately. We sought to develop a simple, noninvasive method of accurately predicting the degree of liver fibrosis in chronic HCV infection. METHODS: We retrospectively studied 211 consecutive patients with chronic HCV, who received a liver biopsy at the Liver Center of the University of California, San Diego. A total of 58 of these patients had a positive history of alcohol abuse, and we analyzed them separately in a sensitivity analysis. AST/ALT ratio and platelet counts were determined in all patients. Fibrosis was staged using the METAVIR score. RESULTS: Both AST/ALT ratio and platelet counts correlated significantly with the disease stage (r = 0.190, p = 0.006, and r = -0.543, p < 0.00, respectively). In a sensitivity analysis, there was no correlation between AST/ALT ratio and disease stage for patients with a history of alcohol abuse. For patients without history of alcohol abuse, the correlation between disease stage, AST/ALT ratio, and platelet counts was r = 0.297, p < 0.00, and r = 0.560, p < 0.00, respectively. In these patients, AST/ALT ratio > or =1 in combination with a platelet count of <150,000/mm3 can identify patients with severe fibrosis or cirrhosis (stages 3 and 4) with a positive predictive value of 93.1%. Sensitivity, specificity, and negative predictive value were 41.2%, 99.1%, and 85.0%, respectively. In patients with ALT/AST ratio of <1 or platelet counts of >150,000/mm3, these laboratory parameters cannot predict liver fibrosis stage. CONCLUSION: AST/ALT ratio in combination with platelet counts may obviate a liver biopsy for fibrosis staging in some patients with chronic HCV infection.