Use of Thiazolidinediones and the Risk of Colorectal Cancer in Patients With Diabetes: A nationwide, population-based, case-control study

OBJECTIVE: Preclinical data suggest that peroxisome proliferator–activated receptor γ (PPARγ) agonists have antineoplastic effects in colorectal cancer. We aimed to assess the association between the use of synthetic PPARγ agonists, represented by thiazolidinediones (TZDs), and the risk of developing colorectal cancer. RESEARCH DESIGN AND METHODS: We conducted a nationwide, population-based, case-control study using the Taiwan National Health Insurance Research Database. Case subjects were defined as patients who were diagnosed with diabetes at least 365 days prior to a new diagnosis of colorectal cancer between 2000 and 2008. We randomly selected diabetic control subjects for each case subject, which were matched by sex, age, and the duration of diabetes. Among the 24,496 eligible case subjects and control subjects, we used conditional logistic regression to assess the risk of colorectal cancer in association with the use of TZDs. An additional analysis was conducted to assess the effects of concomitant use of TZDs and low-dose aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) on the risk of colorectal cancer. RESULTS: A decreased risk of colorectal cancer was observed in patients who had used TZDs compared with those who had never used TZDs (adjusted odds ratio 0.86 [95% CI 0.79–0.94]). Furthermore, the benefit of a decreased colorectal cancer risk was also found with concomitant use of TZDs and low-dose aspirin or NSAIDs. CONCLUSIONS: The use of TZDs may be associated with a decreased risk of colorectal cancer in patients with diabetes. Further studies are warranted to confirm our findings.