A statistically significant increased risk of bladder cancer was not found with the use of pioglitazone, although a small increased risk could not be excluded, according to an analysis published in JAMA.

Prior studies have suggested an increased risk of bladder cancer in patients with diabetes receiving pioglitazone. Study authors from Kaiser Permanente Northern California assessed several cohorts of patients with diabetes, including a bladder cancer cohort (n=193,099) until December 2012, and an additional cohort of 10 cancers (n=236,507) until June 2012. Additional cancers included prostate, breast (female), lung/bronchus, endometrial, colon, non-Hodgkin lymphoma, pancreas, kidney/renal pelvis, rectum, and melanomas.

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The results showed no statistically significant increase in bladder cancer with use of pioglitazone. Among the bladder cancer cohort, 34,181 patients received pioglitazone for a mean duration of 2.8 years, and 1,261 had bladder cancer. In case-control analyses, pioglitazone use was seen in 19.6% of case patients and 17.5% of control patients. In addition, though there was no association of increased cancer risk in eight of the 10 additional cancers, use of pioglitazone was associated with an increased risk of pancreatic and prostate cancer.

Further studies are needed to investigate the cause of the increased risk of pancreatic and prostate cancer with ever use of pioglitazone, researchers concluded.

For more information visit JAMAnetwork.org.