Impact of Diabetes Mellitus and Insulin on Nonalcoholic Fatty Liver Disease in the Morbidly Obese

Introduction and aim. The prevalence of obesity, type 2 diabetes mellitus and non-alcoholic fatty liver disease are increasing. Type 2 diabetes mellitus may aggravate non-alcoholic fatty liver disease, increasing the risk of developing cirrhosis and hepatocellular carcinoma. This study aims to determine the effect of type 2 diabetes mellitus and insulin therapy on non-alcoholic fatty liver disease in the patients with morbid obesity. Material and methods. Clinical, anthropometric and laboratory data were analyzed together with intraoperative liver biopsies from morbidly obese patients undergoing bariatric surgery. Results. 219 patients with morbid obesity were evaluated. Systemic arterial hypertension (55.9% vs. 33.8%, p = 0.004) and dyslipidemia (67.1% vs. 39.0%, p < 0.001) were more prevalent in patients with diabetes when compared to patients without diabetes. In multivariate analysis, type 2 diabetes mellitus was an independent risk factor for severe steatosis (RR = 2.04, p = 0.023) and severe fibrosis (RR = 4.57, p = 0.013). Insulin therapy was significantly associated with non-alcoholic steatohepatitis (RR = 1.89, p = 0.001) and fibrosis (RR = 1.75, p = 0.050) when all patients were analysed, but when only patients with diabetes were analysed, insulin therapy was not associated with non-alcoholic steatohepatitis or fibrosis. Conclusion. Type 2 diabetes mellitus plays an important role in the progression of non-alcoholic fatty liver disease as an independent risk factor for severe fibrosis.