Diagnostic value of biochemical markers (NashTest) for the prediction of non alcoholo steato hepatitis in patients with non-alcoholic fatty liver disease

Background: Liver biopsy is considered the gold standard for assessing histologic lesions of non-alcoholic fatty liver disease (NAFLD). The aim was to develop and validate a new biomarker of non alcoholic steato hepatitis (NASH) the NashTest (NT) in patients with NAFLD. Methods: 160 patients with NAFLD were prospectively included in a training group, 97 were included in a multicenter validation group and 383 controls. Histological diagnoses used Kleiner et al's scoring system, with 3 classes for NASH: Not NASH, Borderline, NASH). The area under the ROC curves (AUROC), sensitivity ( Se), specificity (Sp), and positive and negative predictive values (PPV, NPV) were assessed. Results: NT was developed using patented algorithms combining 13 parameters: age, sex, height, weight, and serum levels of triglycerides, cholesterol, alpha2macroglobulin, apolipoprotein A1, haptoglobin, gamma-glutamyltranspeptidase, transaminases ALT, AST, and total bilirubin. AUROCs of NT for the diagnosis of NASH in the training and validation groups were, respectively, 0.79 (95% CI 0.69 - 0.86) and 0.79 ( 95% CI 0.67 - 0.87; P = 0.94); for the diagnosis of borderline NASH they were: 0.69 ( 95% CI 0.60 - 0.77) and 0.69 ( 95% CI 0.57 - 0.78; P = 0.98) and for the diagnosis of no NASH, 0.77 ( 95% CI 0.68 - 0.84) and 0.83 ( 95% CI 0.67 - 0.90; P = 0.34). When the two groups were pooled together the NashTest Sp for NASH = 94% ( PPV = 66%), and Se = 33% ( NPV = 81%); for borderline NASH or NASH Sp = 50% ( PPV = 74%) and Se = 88% ( NPV = 72%).