Utility of enhanced liver fibrosis and other non-invasive tests in detecting liver fibrosis in patients undergoing bariatric surgery.

BACKGROUND: The presence of metabolic dysfunction-associated steatotic liver disease and liver fibrosis in patients with obesity is associated with poor long-term liver-related outcomes. Liver biopsy is the gold standard. The enhanced liver fibrosis (ELF) panel is a non-invasive test (NIT) with an excellent correlation with liver fibrosis in various liver disorders. The diagnostic utility of this test in the obese population is not yet established. This study aims to assess the diagnostic accuracy of ELF and other NITs in predicting significant and advanced liver fibrosis in obese patients undergoing bariatric surgery. PATIENTS AND METHODS: This prospective cohort study was performed in a tertiary care academic institute in India. All patients underwent standard pre-operative workup according to the institute protocol. Pre-operative NIT values were determined, which included ELF, liver stiffness measurement (LSM) by FibroScan, aspartate aminotransferase-to-platelet ratio index and fibrosis-4 index. The fibrosis stage was graded based on findings of the liver biopsy performed intraoperatively. RESULTS: On liver biopsy, significant fibrosis was present in 13 (33.3%) patients, while advanced fibrosis was present in 7 (17.9%) patients. ELF accuracy improved with fibrosis severity (area under the receiver operating characteristic curve: 0.7-0.9), with best performance for ≥F3 (85.7% - sensitivity, 82.8% - specificity and negative predictive value [NPV] - 96%). LSM demonstrated high sensitivity (83%-95%) but lower specificity, with consistently high NPV (88.9%-95.6%). CONCLUSION: ELF score and LSM demonstrated good diagnostic accuracy to identify liver fibrosis in obese patients undergoing bariatric surgery. Multi-centre studies involving larger sample sizes are needed for optimisation of ELF cut-off values to predict liver fibrosis.