Serum biochemical markers accurately predict liver fibrosis in HIV and hepatitis C virus co-infected patients

OBJECTIVE: Liver biopsy, the gold standard for assessing hepatitis C virus (HCV)-related fibrosis, is invasive and prone to complications. Our aim was to determine the operating characteristics of a non-invasive index of biochemical markers for the prediction of fibrosis in patients with HIV/HCV co-infection. DESIGN: In a cross-sectional, cohort study in a French tertiary-care hospital 130 HIV/HCV-co-infected patients with a liver biopsy and serum were tested for markers of liver fibrosis. METHODS: An index incorporating age, sex, alpha(2)-macroglobulin, apolipoprotein A1, haptoglobin, bilirubin, and gamma-glutamyl-transpeptidase (GGT), derived using multivariate logistic regression, was compared with liver histology. HIV-specific indices including the CD4 cell count and HIV-RNA load were also constructed. The diagnostic values of the indices were compared using receiver operating characteristic (ROC) curves. MAIN OUTCOME MEASURE: Septal fibrosis (F2-F4) by the METAVIR classification. RESULTS: By multivariate analysis, the most informative markers were alpha(2)-macroglobulin, apolipoprotein A1, GGT, and sex. The area under the ROC curve of the five-marker index was 0.856 +/- 0.035; not significantly different from the HIV-specific indices. On a scale from zero to 1.00, the five-marker index had a positive predictive value of 86% for scores greater than 0.60, and a negative predictive value of 93% for scores of 0.20 or less. These thresholds could reduce the necessity for liver biopsy by 55% while maintaining an accuracy of 89%. CONCLUSION: An index including five biochemical markers accurately predicts significant fibrosis in patients with HIV/HCV co-infection, and may substantially reduce the necessity for liver biopsy.