Use of an a-Glucosidase Inhibitor and the Risk of Colorectal Cancer in Patients With Diabetes: A Nationwide, Population-Based Cohort Study

OBJECTIVE Acarbose, an a-glucosidase inhibitor, has been shown to have antineoplastic effects on colorectal cancer in biomarker studies. We assessed the association between acarbose use in patients with diabetes and incident colorectal cancer. RESEARCH DESIGN AND METHODS We conducted a nationwide, population-based study using a large cohort with diabetes in the Taiwan National Health Insurance Research Database. Patients with newly diagnosed diabetes (n = 1,343,484) were enrolled between 1998 and 2010. One control subject not using acarbose was randomly selected for each subject using acarbose after matching for age, sex, diabetes onset, and comorbidities. Cox proportional hazards regression with a competing risks analysis was used to calculate the hazard ratios (HRs) and 95% Cls for the association between acarbose use and incident colorectal cancer for each eligible case-control pair (n = 199,296). RESULTS There were 1,332 incident cases of colorectal cancer in the cohort with diabetes during the follow-up period of 1,487,136 person-years. The overall incidence rate was 89.6 cases per 100,000 person-years. Patients treated with acarbose had a 27% reduction in the risk of colorectal cancer compared with control subjects. The adjusted H Rs were 0.73 (95% CI 0.63-0.83), 0.69 (0.59-0.82), and 0.46 (0.37-0.58) for patients using >0 to <90, 90 to 364, and >= 365 cumulative defined daily doses of acarbose, respectively, compared with subjects who did not use acarbose (P for trend < 0.001). CONCLUSIONS Acarbose use reduced the risk of incident colorectal cancer in patients with diabetes in a dose-dependent manner.