Noninvasive Fibrosis Screening in Fatty Liver Disease Among Vulnerable Populations: Impact of Diabetes and Obesity on FIB-4 Score Accuracy

OBJECTIVE: Fatty liver disease (FLD) is prevalent in diabetes, and both disproportionately affect vulnerable populations. The FIB-4 index is recommended to screen for advanced liver fibrosis. Limited data have suggested that diabetes may impact FIB-4. RESEARCH DESIGN AND METHODS: We evaluated FIB-4 accuracy for advanced fibrosis compared with liver biopsy in the presence of diabetes and obesity. RESULTS: Among 363 FLD patients receiving care in San Francisco's safety net health care system from August 2009 to February 2020, characteristics were as follows: median age 51 years, 46% male, 59% Hispanic, 68% obese, 33% with diabetes, and 31% with advanced fibrosis on histology. Overall, the c-statistic for FIB-4 was 0.79, but was worse in patients with diabetes, 0.68, than without, 0.85 (P = 0.003). Accuracy also varied by weight, at 0.65, 0.85, and 0.75 for normal weight, overweight, and obese, respectively, although not significantly (P = 0.24). CONCLUSIONS: The findings highlight limitations of FIB-4 in screening for advanced liver fibrosis, particularly in individuals with diabetes.