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Controversial diabetes drug use down

August 23, 2008 Toronto

The publication of high-profile drug studies can result in rapid changes in physician’s prescribing practices. New research from Ontario’s Institute for Clinical Evaluative Sciences (ICES) shows a highly publicized study regarding rosiglitazone’s (Avandia) potential harms led to an abrupt decline in new users of the drug, as well as a surge in new use of pioglitazone (Actos) in the treatment of type 2 diabetes.

Lead investigator and ICES scientist, Dr. Baiju Shah notes, “When a high profile study came out last year suggesting that Avandia is bad for you, doctors stopped using it for people needing escalation of their diabetes treatment. This is the first time we’ve seen a prescribing change so quickly following this type of study, and it shows that media exposure can influence health care.” To further explore this issue, ICES investigators examined the prescription records of all Ontario residents, 66 years and older. For each week between January and December 2007, ICES identified new users of five categories of glucose-lowering medications: rosiglitazone, pioglitazone, metformin, glyburide and insulin. Following the release of the meta-analysis*, there was a sudden decline in new users of rosiglitazone, mirrored by a nearly identical but transient increase in new users of pioglitazone (both are competitor medications of the thiazolidinedione or glitazone class). New users were identified as someone who received a first prescription for a particular medication following at least one year without any prescriptions for that medication. Although new rosiglitazone use was falling steadily throughout 2007, there was an abrupt decline following the release of the meta-analysis. There was also a net decline in new users of thiazolidinediones as a class, sometimes referred to as glitazones, as an additional therapy for diabetes (type 2) and related diseases. The number of new users of other glucose-lowering medications did not change.

“What this study shows is that widespread media attention on medical research studies seems to have an impact on physicians’ prescribing behavior,” says Dr. Shah. “All of this attention benefits the patient and helps them make an informed medical decision and sometimes, it just may save their life.”

*Meta-analysis is the examination of all studies in a specific area and seeks to combine the results of various studies addressing the same question. By statistically combining the results of similar studies we can improve the precision of our estimates of treatment effect can be improved. A meta-analysis was published on-line by the New England Journal of Medicine on May 21, 2007, suggesting an increased risk of myocardial infarction (heart attacks) associated with rosiglitazone (Avandia). The thiazolidinediones (rosiglitazone and pioglitazone) are drugs that work by improving the body’s sensitivity to insulin, one of the primary defects in type 2 diabetes.

Author affiliations: ICES (Drs. Shah, Juurlink, Austin, Mamdani); Department of Medicine, University of Toronto (Drs. Shah, Austin, Jurrlink, Mamdani); Department of Medicine, Sunnybrook Health Sciences Centre (Drs. Shah, Jurrlink); Department of Public Health Sciences, University of Toronto (Dr. Austin); Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael’s Hospital (Dr. Mamdani) -- Ontario.

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of health care issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting health care needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.

FOR FURTHER INFORMATION PLEASE CONTACT:

  • Kristine Galka
  • Media Advisor, ICES
  • 416-480-4780 or 416-629-8493
  • kristine.galka@ices.on.ca

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