Pioglitazone and the risk of bladder cancer: An Indian retrospective cohort study

AIM: To determine whether pioglitazone is associated with an increased risk of bladder cancer among Indian type 2 diabetic patients. METHODS: A retrospective data analysis of 2222 type 2 diabetic patients was conducted. The study subjects were divided into two equal groups: 1111 pioglitazone users and 1111 pioglitazone non-users. The safety of pioglitazone therapy was analyzed in terms of occurrence of bladder and other types of cancers along with its efficacy in terms of glycemic control. Parameters for assessing safety were duration of disease, duration of usage and total dose of pioglitazone consumed across age groups, glycemic control, obesity and family history of any cancer. Bladder cancer prevalence was analyzed on the basis of urinary cytology, urine routine and microscopy, hematuria, urinary nuclear matrix protein 22 analysis and ultrasonography. RESULTS: Of the 2222 cases analysed, there was no evidence of bladder cancer in any of the studied groups, (p=not significant) which was also evident among 1111 patients on Pioglitazone therapy with a cumulative dose consumption of 2737 mg to 1,31,400 mg. On subgroup analysis, there was no evidence of bladder cancer amongst patients with age >60 years, duration of diabetes > 10 years and uncontrolled diabetics (HbA1c >8%) with cumulative pioglitazone consumption of >28,000 mg. A significant number of patients achieved good glycemic control (HbA1c <7.5%) with pioglitazone therapy. CONCLUSION: Pioglitazone therapy was not associated with occurrence of bladder cancer among Indian type 2 diabetic patients and demonstrated good glycemic control.