The use of pioglitazone, a thiazolidinedione (TZD), may increase the risk of bladder cancer in patients with type 2 diabetes. In this study, we assessed the risk of bladder cancer associated with the use of TZDs and between pioglitazone and rosiglitazone, an alternative TZD.
Methods We conducted a retrospective cohort study of patients with type 2 diabetes mellitus who initiated treatment with a TZD (n = 18 459 patients) or a sulfonylurea (SU) (n = 41 396 patients) between July 1, 2000, and August 31, 2010, using The Health Improvement Network database in the United Kingdom. Incident cancers were identified for 196 708 person-years of follow-up. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of bladder cancer in the TZD cohort compared with the SU cohort (referent), adjusted for potential confounders. Risk associated with increasing duration of drug exposure was also examined. All statistical tests were two-sided. Read more