Background:  The degree of liver fibrosis is determinant for prognosis of chronic hepatitis C virus (HCV) infection and for initiation of therapy. Liver biopsy is the current invasive, risky, and costly gold standard, but various alternative biological markers have been developed. The aim of this study is to assess the clinical value of a panel of simple biological markers of liver fibrosis in a prospective cohort of HCV/HIV-co-infected patients from a university hospital.

Methods:  From January 1998 to August 2007, before deciding on HCV therapy, fibrosis was assessed in liver biopsies of 353 consecutive HCV/HIV-co-infected patients:  72% males, 81% with a history of intravenous drug use (IDU), and with a mean age of 38.3 years at the time of biopsy. All cases were currently asymptomatic HIV and HCV infections, with a mean CD4 count of 551 cells/µL; 66% were on HAART. Liver fibrosis was determined using a Scheuer's or METAVIR score. Serum samples obtained within <120 days of biopsy were used to build serological non-invasive indexes of fibrosis including aspartate aminotransferase/alanine aminostransferase (AST/ALT) ratio and platelet count (Pohl score), AST platelet ratio index (APRI), Forns, and FIB-4.

Results:  The indexes showed the best performance in the differentiation between significant fibrosis (stages 3 or 4; 28% of biopsy results) and other fibrosis stages (0-2), with area under ROC curve of 0.766 (FIB-4), 0.742 (APRI), 0.710 (Forns), and 0.598 (AST/ALT), respectively. Using the best cut-off score described for the indexes in predicting significant fibrosis (stage 3-4 vs 0-2), we obtained predictive positive and negative values of 0.35 and 0.74 (AST/ALT ratio), 0.53 and 0.74 (Pohl score), 0.58 and 0.81 (APRI), 0.62 and 0.92 (Forns), and 0.74 and 0.76 (FIB-4).

Conclusions: The evaluated non-invasive markers may be useful in predicting liver fibrosis in many patients, but sensitivity and specificity results obtained in our cohort of HCV/HIV-co-infected patients do not permit, at the individual level, replacement of histological examination to identify fibrosis or for prognostic and therapeutic advice.