BACKGROUND: Although an increasing number of noninvasive fibrosis markers are available in HCV-monoinfected patients, data on the performance of these tests in HIV-HCV-coinfected patients are lacking. OBJECTIVE: To assess the diagnostic performance for predicting hepatic fibrosis stage of four simple and inexpensive noninvasive indexes (FIB-4, APRI, Forns, and platelet count) in HIV-HCV-coinfected patients. METHODS: Two hundred consecutive HIV-HCV-coinfected patients from the ANRS-CO3 Aquitaine cohort who underwent liver biopsy were studied. Fibrosis stage was assessed according to Metavir scoring system by a single pathologist unaware of the data of the patients. Diagnostic performances were assessed by measuring the areas under the receiver operating characteristic curves (AUROC) and the percentage of patients correctly identified (PCI). RESULTS: For predicting significant fibrosis (F > or = 2), APRI, Forns index, and FIB-4 had AUROCS of 0.77, 0.75, and 0.79, with 39%, 25%, and 70% of PCI, respectively. For predicting severe fibrosis (F > or = 3), FIB-4 had AUROC of 0.77 with 56% of PCI. For predicting cirrhosis (F4), FIB-4, APRI, and platelet count had AUROCs of 0.80, 0.79, and 0.78, with 59%, 60%, and 76% of PCI, respectively. Overall, diagnostic performances of the different indexes did not differ significantly for both significant fibrosis and cirrhosis. CONCLUSION: The use of these noninvasive indexes could save liver biopsies in up to 56-76% of cases for the prediction of severe fibrosis-cirrhosis. However, given the high percentage of misclassified cases for significant fibrosis, such indexes do not appear currently suitable for use in clinical practice in HIV-HCV-coinfected patients.