Lead author Dr. Ronac Mamtani of the Perelman School of Medicine at the University of Pennsylvania and colleagues analyzed 60,000 type 2 diabetes patients from the Health Improvement Network database in the United Kingdom.
The study, published in the Journal of the National Cancer Institute, found the patients taking TZDs were two-to-three times more likely to develop bladder cancer than those who took a sulfonylurea drug, another common class of medications for diabetes.
The researchers found patients treated with the TZD drugs pioglitazone, or Actos; or rosiglitzaone, or Avandia; for five or more years had a two-to-three-fold increase in risk of developing bladder cancer when compared to those who took sulfonylurea drugs.
Among patients taking TZDs for that length of time, the team's analysis indicates 170 patients per 100,000 would be expected to develop bladder cancer, while about 60 in 100,000 of those who take sulfonylurea drugs such as glipizide, or Glucotrol, would be expected to develop bladder cancer.
"There are many factors clinicians must weigh in deciding which drug to use to control a patient's diabetes, and these new data provide important information to include in that decision-making process," Mamtani said in a statement."