Department of Medicine, Division of Gastroenterology, University of California, San Diego, La Jolla, CA 92093, USA.
Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) frequently coexist due to shared risk factors. Their rising prevalence parallels the growing epidemic of obesity and insulin resistance (IR). In patients with T2DM and biopsy-proven NAFLD, a significantly higher prevalence of nonalcoholic steatohepatitis (NASH) (63-87%), any fibrosis (22-60%), and advanced fibrosis (4-9%) is noted. Possible risk factors for more advanced liver disease include concomitant metabolic syndrome with three or more components, visceral obesity, older age, increased duration of diabetes, and family history of diabetes. Liver biopsy is strongly suggested in these patients. Cardiovascular disease (CVD) and malignancy are the leading causes of death in this population, but a growing body of evidence shows liver-related mortality as an important cause of death, including an increased rate of hepatocellular carcinoma (HCC) in diabetes. The presence of NAFLD in T2DM is also associated with increased overall mortality. We aim with this review to summarize the results from studies investigating NAFLD in T2DM and to outline the factors that predict more advanced liver histology as well as the impact of these hepatic changes on CVD, overall and liver-related mortality.