Diabetes mellitus heightens the risk of hepatocellular carcinoma except in patients with hepatitis C cirrhosis

OBJECTIVES:As most hepatocellular carcinoma (HCC) patients have cirrhosis, the association between diabetes and HCC may be confounded by the fact that diabetes is common in patients with cirrhosis. The aim of this study is to investigate whether diabetes increases the risk of HCC in patients with cirrhosis and whether the etiology of liver disease modifies the association between diabetes and HCC.METHODS:All liver cirrhosis patients who had repeated radiographic evaluation of the liver (that is, ultrasound, computed tomography, or magnetic resonance image) at Mayo Clinic Rochester between January 2006 and December 2011 were included. The Cox proportional hazard regression analysis was used to investigate the effect of diabetes on the risk of HCC.RESULTS:A total of 739 patients met the eligibility criteria, of whom 253 (34%) had diabetes. After a median follow-up of 38 months, 69 (9%) patients developed HCC. In patients without hepatitis C virus (HCV) infection, diabetes was significantly associated with the risk of developing HCC (hazard ratio (HR)=2.1, 95% confidence interval (CI)=1.1-4.1), whereas in patients with HCV, there was no association (HR=0.8, 95% CI=0.4-1.8). When adjusted for covariates, the interaction between HCV and diabetes remained significant (HR for non-HCV=1.9, 95% CI=0.9-3.7; HR for HCV=0.6, 95% CI=0.2-1.3). Lack of association between diabetes and HCC was externally validated in 410 patients with HCV cirrhosis enrolled in the HALT-C trial.CONCLUSIONS:Diabetes increases the risk of HCC in patients with non-HCV cirrhosis. In HCV cirrhosis patients who already have very high risk, diabetes may not increase the risk any further.