Performance of Noninvasive Liver Fibrosis Scores in the Morbid Obese Patient, Same Scores but Different Thresholds

Introduction Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. It is a spectrum of progressive alterations, with the final step in liver fibrosis which carries a high burden of long-term mortality. The scores used to predict liver fibrosis are not properly validated in morbid obesity (MO). Our aim was to evaluate the performance of seven risk scores in bariatric surgery (BS) patients. Methods Cross-sectional analysis in a cohort of 60 patients with MO undergoing BS. Liver biopsy (LB) was taken and compared with fibrosis risk assessed by noninvasive scores: APRI, FIB-4, Forns, NFS (NAFLD fibrosis score), BARD, BAAT, and Hepamet. The area under the receiver operator characteristic curve (AUROC) and measures of diagnostic accuracy were calculated; performance of fibrosis scores was evaluated at standard threshold vs those suggested by ROC analysis. Results LB was available in 50 patients; 9 (18%) had significant fibrosis (F2-F4). The BARD and Forns scores best predicted the absence of fibrosis, both with negative predictive value (NPV) of 95.5%, with AUROC of 0.761 and 0.667, respectively. Modification of standard thresholds (2 for BARD and 6.9 for Forns) to those suggested by ROC analysis (3 and 3.6, respectively) improved performance of scores. Basal glucose, glycated hemoglobin (HbA1c), aspartate transaminase (AST), and gamma glutamyl transferase (GGT) were identified by logistic regression analysis as independent predictor of fibrosis. Conclusions Existing scoring systems are unable to stratify fibrosis risk in MO using established thresholds; its performance is improved if these cutoffs are modified.