aDepartment of Digestive Diseases and Internal Medicine, Division of Internal Medicine bDivision of Surgery and Liver Transplantation, S. Orsola-Malpighi University and General Hospital, Bologna cDepartment of Clinical Sciences and Community Health, University of Milan dUnit of Medical Statistics, Biometry and Bioinformatics, Fondazione IRCCS National Cancer Institute Milan, Milan eUnit of Infectious Diseases and Hepatology, University Hospital, Parma fVenetian Institute of Molecular Medicine (VIMM), University of Padova, Padova gDivision of Internal Medicine, Ospedale di Rimini, Rimini, Italy.
Staging liver fibrosis in chronic viral hepatitis C (HCV) patients is essential for prompting surveillance and treatment. The aim of this study was to develop a nomogram, on the basis of simple clinical and laboratory variables, to predict three clinically significant stages of fibrosis (nil-mild, moderate, advanced/cirrhosis), using histology as reference, and to compare its performance with that of FibroTest, a widely used noninvasive fibrosis score.
MATERIALS AND METHODS:
Nomograms are graphical representations of a mathematical formula, used as predictive tools. The study retrospectively recruited 406 HCV patients undergoing liver biopsy. Nomogram was developed in a training set of 252 patients and tested in a validation set of 154 patients. Histology was staged according to the Metavir system. Fibrosis stages were subgrouped as follows: advanced fibrosis/cirrhosis (F3/F4, 24%), nil-mild (F0/F1, 36%), and moderate (F2, 40%). Age at biopsy, aspartate aminotransferase, γ-glutamyl transpeptidase, albumin, platelet count, and prothrombin activity formed the basis for the so-called Fibro-Nomogram, which, in one graphical representation, estimates probability for different stages of fibrosis.
Areas under the receiver-operating characteristic curves for advanced fibrosis/cirrhosis were similar for training (0.86) and validation sets (0.87). For nil-mild fibrosis, area under the receiver-operating characteristics were 0.81 and 0.79. Compared with FibroTest, Fibro-Nomogram performed slightly better at predicting severe fibrosis (F3/F4) with positive likelihood ratio (LR+) 5.07 (95% confidence interval 3.08-8.37) versus LR+ 3.82 (95% confidence interval 2.56-5.71) for FibroTest. For nil-mild fibrosis, the two tests showed limited but comparable performances.
In HCV patients, Fibro-Nomogram, an inexpensive and readily available predictive tool, could enable clinicians to interpret patients' profile, concurrently stratifying patients into three clinically relevant probability categories with good overall performance.