Validity and clinical utility of the aspartate aminotransferase-alanine aminotransferase ratio in assessing disease severity and prognosis in patients with hepatitis C virus-related chronic liver disease.
BACKGROUND The aspartate aminotransferase-alanine aminotransferase ratio (AST/ALT ratio) has been used to noninvasively assess the severity of disease in patients with chronic liver disease (CLD). We previously demonstrated that progressive liver functional impairment is associated with an increase in the AST/ALT ratio. OBJECTIVES To evaluate the reproducibility and transportability of the AST/ALT ratio in a large cohort of patients with different degrees of hepatitis C virus (HCV)-related CLD, to confirm the correlation between progressive impairment of liver function and increase in the AST/ALT ratio, to evaluate whether diagnostic accuracy of the ALT/AST ratio can be improved by using it with other biochemical variables, and to assess the 1-year prognostic capability of the AST/ALT ratio in patients with liver cirrhosis. PATIENTS AND METHODS We retrospectively evaluated 252 patients with HCV-related CLD. The AST/ALT ratio was correlated with the degree of liver fibrosis in patients with chronic hepatitis and with the Child-Pugh score in patients with cirrhosis. All patients had undergone monoethylglycinexylidide (MEGX) testing to evaluate liver function. We assessed the prognostic ability of the AST/ALT ratio in a subset of 63 cirrhotic patients who were followed up for at least 1 year. RESULTS The AST/ALT ratio was more frequently 1 or higher in cirrhotic patients (P<.001). There was a significant correlation between MEGX values and the AST/ALT ratio (r(s) = -0.621, P<.001). Multivariate stepwise logistic analysis showed that AST/ALT ratio, platelet count (PLT), MEGX values, and prothrombin activity were independently associated with the presence of cirrhosis. Combined assessment of the AST/ALT ratio and/or PLT obtained 97.0% positive predictive value and 97.9% negative predictive value for the diagnosis of cirrhosis. The AST/ALT ratio had 81.3% sensitivity and 55.3% specificity in identifying cirrhotic patients who died within 1-year of follow-up. CONCLUSIONS The AST/ALT ratio is both reproducible and transportable in patients with HCV-related CLD. The AST/ALT ratio is correlated with both histologic stage and clinical evaluation. Progressive liver functional impairment is reflected by an increase in the AST/ALT ratio. Noninvasive evaluation by means of the combined AST/ALT ratio and PLT assessment misclassifies only a few cirrhotic patients. In cirrhotic patients, the AST/ALT ratio provides medium-term prognostic information that is no different from that provided by established prognostic scores.