As Dr. Shih-Wei Lai told Reuters Health by email, “In our study, diabetic patients comorbid with liver cirrhosis, hepatitis B, and hepatitis C were at significantly increased risk of developing hepatocellular carcinoma, and the risk associated with hepatitis C was stronger than that with hepatitis B.”
Dr. Lai of China Medical University, Taichung and colleagues note that there is accumulating evidence that patients with diabetes mellitus are more prone to cancer in general and liver cancer in particular. An American study indicated that the risk of HCC in diabetic patients was more than twice that in non-diabetics, and there have been some similar findings in Taiwan.
To clarify the effect of diabetes on HCC risk, the team examined a health insurance database covering 2000 to 2005 and used the information to compare 19,349 newly diagnosed diabetes patients with 77,396 matched controls. Where possible, they were followed until the end of 2008.
The HCC incidence was doubled in diabetics compared with controls (21.0 versus 10.4 per 10,000 person-years), which translated to an adjusted hazard ratio was 1.73, the team found. Hazard ratios were also significantly and independently increased by being male (2.32), and having cirrhosis (8.65), hepatitis B (2.52), and hepatitis C (5.61).
Stratified analyses showed that subjects with diabetes and cirrhosis along with hepatitis C had the greatest elevation in risk (hazard ratio, 72.4).
The researchers then went on to examine the association between HCC and anti-diabetic medication. After adjustment, metformin use was associated with significant protection (hazard ratio, 0.49). This was also true of thiazolidinediones (hazard ratio, 0.56). Taking insulin, sulfonylureas and other agents also reduced the risk, but not significantly.
Overall, given the influence of the studied comorbidities, concluded Dr. Lai, “These observations suggest that patients with these disorders may be the high-risk group that deserves to be closely monitored. The importance of hepatitis C should not be overlooked.”
Am J Gastroenterol 2011.