According to the Office of Minority Health African Americans and Hispanics have the highest prevalence of diabetes. African Americans are 60% are more likely than Non Hispanic whites to be diagnosed with diabetes by a physician. Furthermore, the incidence of hepatocellular carcinoma is two to three times higher in patients with diabetes.
A study performed at the University of Texas Health Center at San Antonio showed that a racial disparity in incidence of hepatocellular carcinoma in men with type 2 diabetes, but without chronic liver disease, was modified by heterogeneous prevention of hepatocellular carcinoma by metformin. Type 2 diabetes is a risk factor for hepatocellular carcinoma, as are hepatitis C virus, hepatitis B virus, alcoholic liver disease, nonalcoholic fatty liver disease, and hemochromatosis.
Hepatocellular carcinoma, or hepatoma, accounts for 75% of hepatic cancers, and is the most aggressive type. It is the fourth commonest cause of cancer-related deaths globally. In 2012 there were 24,696 hepatocellular carcinomas diagnosed in the United States. In 2019 there were an estimated 42,030 new cases of hepatic and intrahepatic bile duct cancers. The study cohort was comprised of 84,433 electronic medical records of men between the ages of 40 to 89 years with type 2 diabetes and without previous chronic liver disease, cancer, cardiovascular disease, or renal disease, within the Veterans Administration Health Care System. None of the patients had been treated with insulin or thiazolidinediones. A total of 79.4% were non-Hispanic White, 15.5% were non-Hispanic Black, 5% were Hispanic.
Logistic regression was used to compare odds ratios for hepatocellular carcinoma by race with and without treatment with metformin. Among patients not using metformin, the risk of hepatocellular carcinoma for non-Hispanic Blacks was 40% that of non-Hispanic Whites. The risk between non-Hispanic Whites and Hispanics was comparable. Metformin reduced the overall risk of hepatocellular carcinoma by 51%. It reduced the risk by 43% for non-Hispanic Whites, 65% for non-Hispanic Blacks, and 69% for Hispanic patients.
The effect of dosage also differed by race. Treatment with over 1000 mg/day of metformin was more effective for Hispanics, neutral for Whites, and less effective for Blacks. The researchers concluded that the effect of metformin upon prevention of hepatocellular carcinoma is robustly modified by race. They suggest further studies of other anti-diabetic drugs in order to learn how to plan anti-diabetes treatment to prevent hepatocellular carcinoma in the various races and lower the demonstrated racial disparity that exists with this disease.