Hepatocellular carcinoma as a leading cause of cancer-related deaths in Japanese type 2 diabetes mellitus patients.

Background: We reported a cross-sectional study on causes of liver injury in Japanese type 2 diabetes mellitus (T2D) patients (JG 2013). We assessed overall and cause-specific mortality risk during follow-up of patients enrolled in JG 2013.
Methods: This was a longitudinal, multicenter cohort study. Of the 5642 Japanese T2D patients who visited T2D clinics of nine hospitals in the original study, 3,999 patients were followed up for an average of 4.5 years. Expected deaths in T2D patients were estimated using age-specific mortality rates in the general population (GP) of Japan. Standardized mortality ratios (SMRs) were calculated to compare mortality between T2D patients and GP.
Results: All-cancer mortality was significantly higher in T2D patients than in the GP [SMR 1.58, 95% confidence interval (CI) 1.33-1.87]. Among malignancies, hepatocellular carcinoma (HCC) conferred the highest mortality risk in T2D patients (SMR 3.57, 95% CI 2.41-5.10). HCC-associated mortality risk in T2D patients remained significantly high (SMR 2.56, 95% CI 1.64-3.97) after adjusting for high positivity rates of hepatitis B surface antigen (1.7%) and anti-hepatitis C virus (5.3%). In T2D patients with platelet counts < 200 × 10 ³ /μl, SMR of HCC increased from 3.57 to 6.58 (95% CI 4.34-9.58). T2D patients with platelet count > 200 × 10 ³ /μl showed no increase in mortality risk (SMR 0.68) of HCC.
Conclusions: HCC-associated mortality risk was the highest among all cancers in Japanese T2D patients. Regular follow-up may be important for T2D patients with platelet counts < 200 × 10 ³ /μl for early detection of HCC.