Pioglitazone use correlated with increased rates of bladder cancer across a large population. The risk of developing bladder cancer also increased with higher dose and longer use of the drug.1
Pioglitizone is a thiazolidinedione medication that can help manage blood sugar levels in patients with type 2 diabetes. This study did not find any associations with rosiglitazone, another thiazolidinedione diabetes medication.
In 2005, a trial suggested an association with bladder cancer and pioglitazone use. Since then, many other studies’ results have been contradictory about whether an association exists.
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This study examined whether pioglitazone use correlated with increased rates of bladder cancer in patients with type 2 diabetes, comparing pioglitazone with other diabetes medications. Researchers examined data from 145 806 patients in the UK Clinical Practice Research Database (CPRD) who were treated for type 2 diabetes for the first time between 2000 and 2013.
Compared with no use of thiazolidinedione, the use of pioglitazone correlated with a 63% increased risk of bladder cancer (121 per 100 000 person years vs 89 per 100 000 person years). That risk increased with increased duration and dosage of pioglitazone use.
Potentially confounding factors such as age, sex, duration of type 2 diabetes, smoking status, and alcohol-related disorders were taken into consideration in the analyses. Further sensitivity analyses did not significantly change the results.
The use of rosiglitazone was not associated with an increased risk of bladder cancer, suggesting that the risk of bladder cancer is specific to pioglitazone and not to its class of drugs.
“The use of pioglitazone is associated with an increased risk of bladder cancer, which varies in a duration dependent and dose dependent fashion. In contrast, rosiglitazone was not associated with an increased risk of bladder cancer in any analysis, suggesting the risk is drug specific and not a class effect,” concluded the authors.
This study was led by Laurent Azoulay, associate professor of oncology, Center for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, and Department of Oncology, McGill University, Montreal, Quebec, Canada.
REFERENCE
1. Tuccori M, Filion KB, Yin H, et al. Pioglitazone use and risk of bladder cancer: population based cohort study [published online ahead of print March 30, 2016]. BMJ. doi:10.1136/bmj.i1541.
