Nonalcoholic fatty liver disease and liver fibrosis in bariatric patients: Tehran obesity treatment study (TOTS)

Abstract

Background: Non-alcoholic fatty liver disease (NAFLD) has become a leading cause of chronic liver disease worldwide. We aimed to study this condition and liver fibrosis in bariatric patients at baseline using ultrasound, NAFLD fibrosis score (NFS), and fibrosis index-4 (FIB-4). Methods: Adult patients with morbid obesity without other possible causes of liver pathology were evaluated. Liver biopsy was performed in a subset of patients. Diagnostic accuracy of tests was assessed using area under the receiver operating-characteristic curve (AUROC). Results: Overall, 1944 patients with mean age of 38.3 ± 10.8 years and body mass index of 44.6 ± 6.4 kg/m2 comprised the study population. Liver Biopsyshowed features of NAFLDin 70; 60.3 hadnonalcoholic fatty liver and9.6 steatohepatitis. Older age and higher transaminase levels were associated with higher NAFLD activity score. Fibrosis was present in 23.3 with the majority having F1. Ultrasound detected steatosis in 76.8, with two-thirds having grade I to II fatty liver. Metabolic syndrome, hemoglobin A1c, age, and alanine transaminase were the strongest risk factors for fatty liver. Ultrasound showed an AUROC of 0.75 (95 confidence interval 0.63-0.86) for NAFLD with a sensitivity and specificity of 72.5 and 68.2, respectively (cutoff of grade II). For diagnosis of fibrosis, FIB-4 had an AUROC of 0.72 (0.58-0.86) with 93.3 sensitivity and 43.1 specificity (cutoff of 0.50). NFS failed to show a significant AUROC curve for diagnosing fibrosis. Conclusions: Our findings confirmed a high prevalence of NAFLD in morbidly obese patients. Despite this high prevalence, fibrosis was uncommon and low-grade. This study questions the use of current cutoffs for NFS and FIB-4 in all patients. © 2018, Hepatitis Monthly