Type 2 diabetes drug linked to increased risk of bladder cancer

The common type 2 diabetes drug Actos (pioglitazone) is associated with an increased risk of bladder cancer, a new study finds.
Actos is part of the anti-diabetic drug class known as thiazolidinediones (TZDs). It works by increasing sensitivity to insulin in people with type 2 diabetes, but this study is not the first to link Actos with the risk of developing bladder cancer.
In this new study, Canadian researchers identified 145,806 patients from the UK Clinical Practice Research Database. The patients had started treatment with anti-diabetic drugs between January 2000 and July 2013.
They were followed until July 2014 and the mean length of follow-up time was 4.7 years, Overall, 622 patients received a diagnosis of bladder cancer during the follow-up period.
The researchers found that compared to other anti-diabetic drugs, pioglitazone was associated with an increased risk of bladder cancer. This risk increased with longer duration of use and higher dose.
No increased risk was found for Avandia (rosiglitazone), a TZD that was banned from use in the UK in 2010 after the European Medicines Agency found it raised the risk of heart disease.
Lead author Dr. Laurent Azoulay, Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada said: “The absence of an association with rosiglitazone suggests that the increased risk is drug specific and not a class effect.”
The researchers added that patients taking the drug should be informed of this risk, and believe the results have implications for prescribing the drug in the future.
They concluded that additional studies with longer follow-up periods are necessary to determine this association between increased bladder cancer risk and pioglitazone.
If you are currently taking Actos, you should not stop taking the drug without first discussing this with your doctor.
The findings appear in The BMJ.