1123 Utility of Non-Invasive Screening Tools for Assessing Liver Fibrosis in Individuals With Medically Complicated Obesity

Abstract

INTRODUCTION: Individuals with medically-complicated obesity are at risk for cirrhosis as the result of chronic nonalcoholic steatohepatitis (NASH). Several cases of acquired ornithine transcarbamylase (OTC) deficiency have been reported after bariatric surgery, and underlying liver disease is hypothesized as a risk factor. Liver biopsy has been the gold standard for diagnosis and staging of fibrosis, but it is not favored as a screening test due to cost, invasive nature of the test. Commercial blood testing for ALT may be useful for screening for NASH, while the NAFLD Fibrosis Score (NFS) has gained popularity to assess fibrosis. We hypothesize that non-invasive screening can identify both at risk individuals in whom bariatric surgery will potentially halt and reverse fibrosis as well as at risk individuals who should be monitored for signs and symptoms of postoperative OTC deficiency METHODS: This is a retrospective study of 593 consecutive individuals evaluated for bariatric surgery at our urban, community teaching hospital. Each individual is assessed for risk of liver fibrosis with NFS evaluated at their initial visit. ALT levels are also recorded using ACG guidelines for elevation (women > 25 U/L; men > 33 U/L). Intraoperative liver biopsies were suggested in individuals with elevated ALT levels or NFS which was > - 0.70. Steatohepatitis on liver biopsies is staged based on the NAFLD Activity Score (NAS), which in previous studies is reported to have a sensitivity of 43% to 77%. The potential correlation between NFS and NAS is assessed with simple linear regression (Statview, SAS Institute Inc.). RESULTS: Among the 593 subjects, 102 (17.2%) had elevated ALT. Forty-nine individuals underwent liver biopsy (6 for elevated ALT and 43 for NFS > -0.70). Table 1 shows the demographics of these patients. The mean NFS was 0.580 (SD: 1.01) and the mean NAS was 2.9 (SD 1.2). Correlation Coefficient (R: 0.025, P = .86) between NFS calculated at the initial visit and NAS on liver biopsies is not significant. CONCLUSION: Elevated ALT levels may be useful for assessment of risk in individuals with medically-complicated obesity. Our retrospective study has not identified a significant correlation between NFS (from routine parameters) and NAS (from liver biopsies). This finding suggests that NFS is not a sensitive non-invasive screening tool in individuals with medically-complicated obesity. Future studies can be designed to utilize ALT levels and NAS to look at the risk of developing postoperative OTC deficiency.