Gallstones, a cholecystectomy, chronic pancreatitis, and the risk of subsequent pancreatic cancer in diabetic patients: A population-based cohort study

Background: The causal association between diabetes and pancreatic cancer remains unclear in Asian populations. This study examined whether gallstones, a cholecystectomy, chronic pancreatitis and the treatment of antidiabetic agents affect the risk of subsequent pancreatic cancer for patients with diabetes in a Taiwanese population. Methods: Using claims data from the universal health insurance program in Taiwan, 449,685 newly diagnosed diabetic cases among insured people from 2000 to 2003 were identified as the case group. The comparison group, matched for gender, age, and the index year of the diabetes cohort, consisted of 325,729 persons without diabetes. Pancreatic cancer incidence was measured in both groups until the end of 2008. Other risk factors associated with this cancer were also measured. Results: The incidence of pancreatic cancer in the diabetic cohort was 2-fold greater than that in the comparison group (1.46 vs. 0.71 per 10,000 person-years) with an adjusted hazard ratio (HR) of 1.75 [95 % confidence interval (CI) 1.45-2.10]. The risk slightly increased for diabetic patients with gallstones, cholecystitis, and a cholecystectomy (HR 1.92, 95 % CI 1.18-3.11), but greatly increased for those with comorbidity of chronic pancreatitis (HR 22.9, 95 % CI 12.6-41.4). Pancreatic cancer risk also increased significantly for those patients who used more insulin for treating diabetes (OR 2.20, 95 % CI 1.40-3.45). Conclusion: Our data suggest that the risk of pancreatic cancer is moderately increased in patients with diabetes, especially those using insulin therapy. The risk is greatly increased for diabetic patients with chronic pancreatitis.