Aspartate aminotransferase: alanine aminotransferase ratio in chronic hepatitis C infection: Is it a useful predictor of cirrhosis?

Background: The clinical usefulness of the ratio of serum aspartate aminotr ansferase (AST) to alanine aminotransferase (ALT) has been explored in seve ral liver disorders. It has been suggested that in patients with chronic he patitis C virus (HCV) infection an AST : ALT greater than or equal to 1 has 100% specificity and positive predictive value in distinguishing cirrhotic from non-cirrhotic patients. Such statistical certainty attached to a simp le biochemical test merits further evaluation. The present study, therefore , assessed the AST : ALT in patients with chronic HCV infection to determin e the validity of the ratio in predicting cirrhosis and to correlate the ra tio with the histological grade of necroinflammatory activity and fibrosis. Methods: A retrospective analysis of 153 patients with chronic HCV infectio n was conducted. Serum biochemistry had been obtained within a mean of 4 we eks of liver biopsy. The histology was scored in terms of activity and fibr osis as described by Scheuer and correlated with AST : ALT. Results: In 30 patients with cirrhosis, the mean AST : ALT (0.99 +/- 0.06) was higher than in 123 patients without cirrhosis (0.60 +/- 0.02; P < 0.001 ). A ratio greater than or equal to 1 had 95.9% specificity and 73.7% posit ive predictive value in distinguishing cirrhotic from non-cirrhotic patient s, with a 46.7% sensitivity and 88.1% negative predictive value. The ratio also parallelled the Scheuer score with respect to fibrosis but not with re spect to inflammation. Conclusion: Although relatively insensitive, an AST : ALT greater than or e qual to 1 is highly specific but not diagnostic for the presence of cirrhos is in patients with chronic HCV infection. The ratio reflects the grade of fibrosis in these patients. (C) 2000 Blackwell Science Asia Pty Ltd.