Is Pioglitazone Associated with Excess Risk for Bladder Cancer?

In a 2012 study of pioglitazone, an oral thiazolidinedione drug used for managing type 2 diabetes, excess risk for bladder cancer was detected (NEJM JW Gen Med Jul 15 2012 and BMJ 2012; 344:3645), whereas a 2015 study showed no excess risk (NEJM JW Gen Med Sep 1 2015 and JAMA 2015; 314:265). In this population-based U.K. cohort study of 146,000 people with type 2 diabetes who were newly treated with antidiabetic drugs during 2000 and 2013, researchers add to the evidence about risk for pioglitazone-associated bladder cancer.

During follow-up (through 2014; mean follow-up, 4.7 years), 622 patients were diagnosed with bladder cancer. After adjusting for multiple variables, pioglitazone use was associated with a relative increase in bladder can…