Visual Liver Score to Stratify Non-Alcoholic Steatohepatitis Risk and Determine Selective Intraoperative Liver Biopsy in Obesity.

Abstract

Non-alcoholic fatty liver disease (NAFLD) and its progressive form, non-alcoholic steatohepatitis (NASH), are endemic in obesity. We aimed to evaluate the diagnostic accuracy and reproducibility of a simple intraoperative visual liver score to stratify the risk of NASH and NAFLD in obesity and determine the need for liver biopsy. This is a prospective cohort study of obese adults undergoing bariatric surgery. The surgical team used a visual liver score to evaluate liver colour, size and surface. This was compared to histology from an intraoperative liver biopsy. There were 152 participants, age 44.6±12years, BMI 45±8.3kg/m2. Prevalence of NAFLD was 70.4%, with 12.1% NASH and 26.4% borderline NASH. Single-visual components were less accurate than total composite score. Steatosis was most accurately identified (significant steatosis: AUROC 0.746, p<0.05; severe steatosis: AUROC 0.855, p<0.05). NASH was identified with moderate accuracy (AUROC 0.746, p=0.001), with sensitivity 75% for a score ≥2. Stratification into low (≤1) and high-risk (≥4) scores accurately identified patients who should or should not have an intraoperative biopsy. Most patients with a normal-appearing liver did not have disease (94.4%). The structured visual assessment was quick and interobserver agreement was reasonable (κ=0.53, p<0.05). A simple, structured tool based on liver appearance can be a useful and reliable tool for NAFLD risk stratification and identification of patients who would most and least benefit from a biopsy. A normal liver appearance reliably excludes significant liver disease, avoiding the need for liver biopsy in patients otherwise at high clinical risk of NASH.