(P-543) The Incidence Rates of Hepatobiliary Diseases Among Non-alcoholic Steatohepatitis Patients Stratified by fibrosis-4 (FIB-4) Index for Liver Fibrosis

Background: Non-alcoholic steatohepatitis (NASH) is an advanced stage of fatty liver disease characterized by liver inflammation and may result in advanced fibrosis and liver failure. The invasive liver biopsy is the gold standard for assessing hepatic fibrosis. Alternatively, fibrosis-4 (FIB-4) index score, a non-invasive diagnostic tool, calculates hepatic fibrosis severity using age and typical biochemical laboratory tests

Objectives: To estimate hepatobiliary outcomes' incidence rates among NASH patients stratified by FIB-4 defined fibrosis severity

Methods: HealthCore Integrated Research Database (HIRD) was used to identify NASH patients from October 2015 to March 2020. The NASH algorithm required either 1. NASH as the principal inpatient discharge diagnosis, 2. liver biopsy followed by NASH diagnosis, or 3. liver imaging followed by NASH diagnosis, liver function procedure, and ≥1 risk factor including obesity, type 2 diabetes, pre-diabetes, or dyslipidemia. No patients with concurrent liver disease or liver transplant history were included. The baseline period was ≥ 12 months of continuous health plan enrollment. FIB-4 scores were estimated based on age, platelet count, AST, and ALT. Published thresholds were used to categorize them as no/early fibrosis (NF), intermediate (IF), or advanced fibrosis (AF). Incidence rates (IR) and 95% confidence intervals of several hepatobiliary diseases were calculated as number of events during follow-up period divided by the total person-time at risk and expressed per 1,000 Person Years (PY)

Results: Of 20,198 qualifying NASH patients, baseline FIB-4 was estimated for 7,937 (40%). Of these, 4,415 (56%) had NF, 2,239 (28%) had IF, and 1,283 (16%) had AF. AF patients were older and more likely to have type 2 diabetes (69% vs. 54% & 38%) and hypertension (83% vs. 77% & 61%) than IF and NF, respectively. The presence of hepatic comorbidities at baseline was greatest among AF, followed by IF and NF, baseline cirrhosis was 63%, 17%, & 5%, respectively. The lowest IR of hepatobiliary diseases were among NF, followed by IF and AF. The IR of cholelithiasis increased from 9.4 (7.1, 12.4,) to 13.0 & 45.8; liver failure increased from 2.1 (1.2, 3.8) to 10.0 & 89.1; cirrhosis increased from 11.5 (9.0, 15.0) to 48.3 & 224.0, respectively

Conclusions: The IR of hepatobiliary diseases had a consistent pattern where NF had the lowest rates, followed by IF and AF during follow-up. FIB-4 scores delineated a higher burden of hepatic comorbidities at baseline among AF compared to IF and NF patients. Our findings provide further evidence supporting the utility of FIB-4 as a prognostic indicator in NASH patients