Type 2 diabetes mellitus increases the risk of hepatic fibrosis in individuals with obesity and nonalcoholic fatty liver disease.

OBJECTIVE This study assessed the impact of diabetes mellitus (DM) on nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) with advanced fibrosis prevalence in adults with overweight or obesity in the United States. METHODS Participants (National Health and Nutrition Examination Survey [NHANES] 2015-2016 database) included 834 middle-aged patients with DM (21.7%) and 3,007 without DM (78.3%). NAFLD was defined by Fatty Liver Index (FLI) ≥ 60 or United States FLI (USFLI) ≥ 30. Moderate-to-high and high risk of advanced fibrosis was defined by fibrosis-4 index (FIB-4) ≥ 1.67 and ≥ 2.67, respectively, and NAFLD fibrosis scores > 0.676 also indicated a high risk. RESULTS NAFLD prevalence increased with BMI. Steatosis was higher in individuals with overweight with DM versus without DM (USFLI ≥ 30: 48.3% vs. 17.4%; p < 0.01) and in individuals with obesity with DM versus without DM (USFLI ≥ 30: 79.9% vs. 57.6%; p < 0.01). DM significantly increased the proportion of individuals at moderate-to-high risk of fibrosis (FIB-4 ≥ 1.67: 31.8% vs. 20.1%; p < 0.05). In the high risk of advanced fibrosis group (FIB-4 ≥ 2.67), the risk almost doubled (3.8% vs. 7.1%). Among individuals with obesity, DM increased the proportion of adults with moderate and high risk of fibrosis by 1.8- and 2.5-fold, respectively (p < 0.01 and p = 0.39, respectively, vs. without DM). CONCLUSIONS In this US cohort, DM modestly impacted steatosis, which was primarily obesity-driven. DM added a significant risk of fibrosis to individuals with overweight or obesity, suggesting that screening is imperative in adults with DM.