ORIGINAL RESEARCH Diagnosis of advanced fibrosis in HIV and hepatitis C virus-coinfected patients via a new noninvasive index: the HGM-3 index S Resino, 1 D Micheloud, 1 P Miralles, 2 JM Bello´n, 3 A Vargas, 1 P Catala´n, 4 EA ´ lvarez, 5 J Cosı ´n, 2 R Lorente, 6 JC Lo´ pez, 2 MA Mun˜ oz-Ferna´ndez 6 and J Berenguer 2 1 Laboratory of Molecular Epidemiology of Infectious Diseases, National Centre of Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, 2 Infectious Diseases-HIV Unit, 3 Biomedical Research Foundation, 4 Microbiology Department, 5 Pathology Department and 6 Molecular Immunobiology Laboratory, Hospital General Universitario ‘Gregorio Maran˜o´n’, Madrid, Spain Background Noninvasive tests are increasingly being used for the assessment of liver fibrosis. We aimed to develop a serum index for the identification of advanced fibrosis (F  3) in HIV/hepatitis C virus (HCV)-coinfected patients. Methods We carried out a cross-sectional study on a group of 195 patients comprised of an estimation group (EG; n 5 127) and a validation group (VG; n 5 68) who all underwent liver biopsy and had not received previous interferon therapy. Liver fibrosis was estimated using the METAVIR score. We developed a new serum index (HGM-3) dependent on levels of platelets, alkaline phosphatase, hepatic growth factor, tissue inhibitor of metalloproteinase-1 and hyaluronic acid. Results In the EG, the area under the receiver operating characteristic curve (AUC-ROC) of HGM-3 for identification of F  3 was 0.939 [95% confidence interval (CI) 0.899, 0.979] which was significantly higher than the AUC-ROC of the HGM-2, FIB-4, aspartate aminotransferase to platelet ratio (APRI) and Forns’ indexes. With HGM-3 o0.135 for Fo3, 57 patients were correctly identified and two patients were misclassified. We found the presence of Fo3 with 96.6% certainty. The negative likelihood ratio (LR) was o0.1 and the diagnostic odds ratio (DOR) was 440. With HGM-3 40.570 in the EG for F  3, 31 patients were correctly identified, and five patients were misclassified. We found the presence of F  3 with 86.1% certainty. The positive LR was 412 and the DOR was 440. For the VG, the diagnostic accuracy values were similar to the values for the EG. Conclusions HGM-3 appears to be an accurate noninvasive method for the diagnosis of bridging fibrosis and cirrhosis in HIV/HCV-coinfected patients. Keywords: liver cirrhosis, serum predictive markers, liver fibrosis, diagnostic accuracy, chronic hepatitis C Accepted 14 May 2009 Introduction HIV infection adversely impacts the natural pathology of hepatitis C virus (HCV) infection, causing a more rapid progression to fibrosis and the development of cirrhosis, hepatic decompensation, hepatocellular carcinoma and death [1–5]. For this reason, all HIV-infected individuals should be screened for HCV infection, and all individuals Correspondence: Dr Salvador Resino, Laboratorio de Epidemiologı ´a Molecular de enfermedades Infecciosas, Centro Nacional de Microbiologia (Instituto de Salud Carlos III), Carretera Majadahonda-Pozuelo, Km 2.2, 28220 Majadahonda (Madrid), Spain. Tel: 1 34 918 223 266; fax: 1 34 915 097 946; e-mail: sresino@isciii.es DOI: 10.1111/j.1468-1293.2009.00745.x HIV Medicine (2010), 11, 64–73 r 2009 British HIV Association 64