Development and validation of a novel scoring system for noninvasive nonalcoholic steatohepatitis detection in bariatric patients

Abstract

Introduction: Nonalcoholic fatty liver disease covers a broad spectrum. Simple steatosis has usually a benign course while nonalcoholic steatohepatitis (NASH) can progress into hepatocellular carcinoma, and cirrhosis. Therefore, differentiating patients with benign steatosis and NASH is crucial. Liver biopsy, the usual gold standard for NASH diagnosis, cannot be used as a screening method due to its associated risks. This is especially problematic for obese patients with a prevalence of nonalcoholic fatty liver disease (NAFLD) in >80% of patients. The aim of this study was therefore to develop and validate a noninvasive NASH screening test in a cohort of high-risk, morbidly obese patients. Methods: This prospective study examined diagnostic accuracy in accordance with STARD guidelines. 112 liver biopsies were consecutively assigned to either a training or validation cohort. Using the Bedossa histological scoring system, the cohorts were subdivided into NASH versus NAFLD/No NAFLD. Predictors of NASH were evaluated with receiver operating characteristic (ROC) curves. A model was then constructed using a backward stepwise logistic regression and evaluated in an independent validation cohort. Results: 53.5% of the patients had NASH and 4 patients had cirrhosis. Mean body mass index (BMI) was 49.8 ± 7.5 kg/m2. Backward stepwise logistic regression identified 4 parameters associated with the presence of NASH: alanin-aminotransferase, albumin, BMI, and triglycerides. The noninvasive NASH detection score (NI-NASH-DS) had an ROC of 0.851 and 0.727 in the training and validation cohorts, respectively. Sensitivity and specificity were 77.1% and 88% in the training cohort and 88% and 48% in the validation cohort which was much better than the established noninvasive scores. Discussion/Conclusion: The NI-NASH-DS is easy-to-use, inexpensive, and noninvasive and can reliably detect NASH in patients with morbid obesity. Due to its simplicity, it can be used frequently and repeatedly.