Spectrum of liver disease in type 2 diabetes and management of patients with diabetes and liver disease.

I t is estimated that 20.8 million people, i.e., 7.0% of the U.S. population, have diabetes (1). Type 2 diabetes, with its core defects of insulin resistance and relative insulin deficiency, accounts for 90– 95% of those with the disease. Another 5.2 million people are estimated to have undiagnosed type 2 diabetes. It is the sixth leading cause of death (1) in the U.S. and accounts for 17.2% of all deaths for those aged 25 years (2). Liver disease is an important cause of death in type 2 diabetes. In the population-based Verona Diabetes Study (3), cirrhosis was the fourth leading cause of death and accounted for 4.4% of diabetesrelated deaths. The standardized mortality ratio (SMR), i.e., the relative rate of an event compared with the background rate, for cirrhosis was 2.52 compared with 1.34 for cardiovascular disease (CVD). In another prospective cohort study (4), cirrhosis accounted for 12.5% of deaths in patients with diabetes. Diabetes, by most estimates, is now the most common cause of liver disease in the U.S. Cryptogenic cirrhosis, of which diabetes is, by far, the most common cause, has become the third leading indication for liver transplantation in the U.S. (5,6). Virtually the entire spectrum of liver disease is seen in patients with type 2 diabetes. This includes abnormal liver enzymes, nonalcoholic fatty liver disease (NAFLD), cirrhosis, hepatocellular carcinoma, and acute liver failure. In addition, there is an unexplained association of diabetes with hepatitis C. Finally, the prevalence of diabetes in cirrhosis is 12.3–57% (7). Thus, patients with diabetes have a high prevalence of liver disease and patients with liver disease have a high prevalence of diabetes. The management of diabetes in patients with liver disease is theoretically complicated by liver-related alterations in drug metabolism, potential interactions between the drugs, and a low, albeit real, incidence of hepatotoxicity. In this article, we review the spectrum of liver disease found in patients with type 2 diabetes and the management of patients with concurrent diabetes and liver disease.