SGLT2 Inhibitor Versus Sulfonylurea on Type 2 Diabetes With NAFLD

Nonalcoholic fatty liver disease (NAFLD), ranging from simple fatty liver to nonalcoholic steatohepatitis (NASH), is a liver phenotype of metabolic disorders, such as diabetes, obesity, and metabolic syndrome. NAFLD and type 2 diabetes share epidemiological and pathophysiological features. Specifically, hyperglycemia is closely associated with liver fibrosis, which is associated with liver cirrhosis, hepatocellular carcinoma, and prognosis in patients with NASH. To date, some anti-diabetic agents have been tested in patients with NAFLD. The guidelines in the Asian Pacific, European, and American association recommended the administration of PPAR gamma agonist (pioglitazone) and glucagon-like peptide receptor agonists (GLP1RA) for the treatment of diabetes with NAFLD/NASH. However, there are concerns about adverse effects such as weight gain, edema, fractures, and carcinogenesis in pioglitazone or gastrointestinal adverse effects and medication burden as an injection in GLP1 RA. In addition, because all of these anti-diabetic agents significantly reduced glycemic levels compared with placebo, liver histological improvement may be theoretically attributable to glucose reduction itself. Both sodium-glucose cotransporter 2 (SGLT2) inhibitors and sulfonylureas are chosen as the second-line therapy when glycemic control cannot be achieved with metformin or as the first-line therapy when metformin is contraindicated or not tolerated. In animal models of NAFLD/NASH, SGLT2 inhibitors protect against steatosis, inflammation, and fibrosis. Previous clinical trials have demonstrated that SGLT2 inhibitors exert protective effects on liver enzymes and liver steatosis in patients with NAFLD/NASH. However, these studies lack a control group or histological examination, which precludes meaningful conclusions since the natural course of the disease or tight glycemic control may ameliorate liver histology in some patients with NAFLD. Sulfonylureas are still reliable and potent antidiabetic agents in insulinopenic patients with type 2 diabetes and therefore are used as the second-line therapy, especially when the cost is a significant issue. Besides, sulfonylureas reduce glucose and elevate weight, which may render positive and negative effects, respectively, on liver pathology in NAFLD/NASH. In the phase 3 trial, canagliflozin was non-inferior to glimepiride for reduction of HbA1c at 52 weeks. However, the differences between SGLT2 inhibitors and sulfonylureas on NAFLD patients with type 2 diabetes under similar glucose reduction remain uncertain.