This Common Diabetes Rx May Be Safer Than Previously Thought

Pioglitazone link to bladder cancer risk unlikely despite concerns

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Weighing the benefits of medications against their potential risks is a common conundrum for many doctors. But, for one common diabetes medication, that decision may have gotten a little easier.

A new study found no significant link between the diabetes medication pioglitazone (Brand name Actos) and bladder cancer, despite previous concerns.

"There was no statistically significant increased risk of bladder cancer associated with pioglitazone use," wrote lead study author Assiamira Ferrara, MD, PhD, of Kaiser Permanente Northern California, and colleagues. "The increased prostate and pancreatic cancer risks associated with ever use of pioglitazone merit further investigation ..."

Pioglitazone is used together with proper diet and exercise to help control blood sugar in adults with type 2 diabetes.

"As a practicing community pharmacist, regularly I have patients come to me with a concern they read on the internet or heard from a friend," said Steve Leuck, PharmD, pharmacist and founder of AudibleRx, in an interview with dailyRx News. "The concern usually describes an unfortunate outcome associated with a treatment that they are currently receiving. My first step is to help the patient re-establish an understanding of why they are currently taking this particular medication treatment."

Dr. Leuck added, "In this particular situation, I would help the patient understand that treating their diabetes helps prevent nerve damage, kidney problems, vision difficulties, decreases heart attack and stroke risk and helps maintain sexual function. If the patient has a family history of cancer, I would encourage them to have a discussion with their physician to discuss this further. In the meantime, I would counsel the patient on the importance of continuing their diabetic treatment and assure them there has been no recent FDA warning issued regarding a link between certain types of cancer and specific diabetes treatment regimens."

Using data from Kaiser Permanente's health records, Dr. Ferrara and team looked at two large groups of patients with diabetes.

The first group involved 193,099 diabetes patients. About 17 percent (34,181) of these patients were prescribed pioglitazone.

These patients were followed for an average of 7.2 years, during which 0.65 percent (1,261) of the 193,099 patients were diagnosed with bladder cancer.

Among those who used the drug, 186 developed bladder cancer — while the same was true for 1,075 patients who had never used pioglitazone.

Dr. Ferrara and team also looked at a group of 236,507 diabetes patients. About 16 percent (38,190) of these patients 38,190 were prescribed the drug.

In this group, cancers other than bladder cancer were observed.

The patients were followed for around 5 years, during which 6.76 percent (15,992) were diagnosed with some form of cancer.

Dr. Ferrara and team found a slightly increased risk of prostate cancer and pancreatic cancer among those who took pioglitazone.

However, no clear pattern emerged connecting pioglitazone use to an increased risk of cancer.

In a related editorial, Joshua M. Sharfstein, MD, of The Johns Hopkins Bloomberg School of Public Health, and Aaron S. Kesselheim, MD, PhD, of Brigham and Women’s Hospital, wrote that this study shows how dynamic and ever-changing questions about drug safety can be.

"As in this case, caution and further review are the appropriate responses to many safety signals," Drs. Sharfstein and Kesselheim wrote. "But when emerging available data... create a compelling picture of risk in excess of potential benefit to patients, the [US Food and Drug Administration] should act to protect the public."

In a separate related editorial, Phil B. Fontanarosa, MD, executive deputy editor of JAMA (which published this study) highlighted the importance of publishing studies that look at the safety of medications.

"Demonstrating no statistically significant association between the use of pioglitazone and the risk of bladder cancer are important because of the prevalence of type 2 diabetes, fairly widespread use of pioglitazone, and safety concerns about this drug," Dr. Fontanarosa wrote.

The study and editorials were all published online July 21 in the journal JAMA.

Takeda (the company that manufactures pioglitazone) funded this research.

Several study authors disclosed financial ties to the pharmaceutical companies Takeda, AstraZeneca and Sanofi.

Review Date: 
July 20, 2015
Last Updated:
July 28, 2015