TORONTO, Dec. 11 /CNW/ - A popular class of drugs for treating type 2
diabetes is under scrutiny again. A new Canadian study released by the
Institute for Clinical Evaluative Sciences (ICES) finds that drugs such as
Avandia increase the risk of heart failure, heart attacks and death.
Published in the December 12th issue of JAMA, ICES scientists looked at
the glitazone class of drugs including rosiglitazone (Avandia) and
pioglitazone (Actos) in the first real world population-based study of its
kind. All Ontario residents aged 65 years or older, treated with at least one
oral diabetic medication were followed between 2002 and 2006. "The necessity
for evaluating diabetes drug outcomes in older patients is reinforced by the
fact that seniors have the highest prevalence of diabetes and represent over
40% of the population with the disease," says lead author and ICES researcher,
Dr. Lorraine Lipscombe. "We cannot be certain whether similar effects would be
seen in younger patients. Our study represents a concern for older patients
taking these drugs who are at higher risk for adverse cardiac outcomes."
The ICES study explored three distinct outcomes using Ontario health care
databases: hospital visits for congestive heart failure, hospital visits for
heart attacks and death from any cause, and looked at exposure to specific
diabetes drugs in seniors. Compared to other diabetes pills glitazones
(Avandia & Actos ) are associated with the following results:
- 60% relative increase in heart failure, 40% relative increase in
heart attacks, 30% relative increase in death.
- This translates into an estimated 3 additional episodes of heart
failure, 4 additional heart-attacks and 5 additional deaths for every
100 individuals taking these drugs, over a 4 year period in a high-
risk older population.
- Risk predominantly among those taking rosiglitazone (Avandia).
- Smaller numbers of people received the other drug pioglitazone
(Actos), limiting our ability to be certain about adverse events in
Co-author and Senior ICES Scientist, Dr. David Alter says, "We don't want
people to panic. Treatment decisions must remain individualized with doctors
and patients weighing the potential harms and benefits of these drugs,
especially when used among the elderly who are at higher-risk of cardiac
The Ontario based ICES study comes on the heels of the Food and Drug
Administration (FDA) slapping a prominent black box label warning on the
popular diabetes drug Avandia telling patients that it may, or may not,
increase the risk of heart attacks. It is the most severe type of warning the
agency can require pending further research. Glaxo Smith Kline, Avandia's
manufacturer has agreed to do a longer term study comparing the drug to other
medications, but those results won't be available for another six years. Since
the drug's approval in 1999, more than 7 million people worldwide have taken
Avandia, designed to increase the body's sensitivity to insulin, generating
sales worth $3 billion annually.
"Our study demonstrates the importance of post-marketing surveillance of
new drugs. Manufacturers are often required to only demonstrate diabetes
medications lower blood sugar not that they prevent long term consequences of
diabetes. Research trials are often insufficient to detect less common adverse
effects of drugs, so ongoing safety monitoring of drug side effects in larger
real-world populations is vital. Experts from regulatory bodies such as Health
Canada and the Food and Drug Administration will have to consider our findings
in the context of all the evidence so far, to decide the future of these
drugs," says Dr. Lipscombe.
The study 'Thiazolidinediones and Cardiovascular Outcomes in Older
Patients with Diabetes' is in the December issue of JAMA.
Author affiliations: ICES (Drs. Lipscombe, Hux, Juurlink, Alter, Ms.
Gomes, Levesque); (Drs. Lipscombe, Hux, Juurlink, Alter) Department of
Medicine, University of Toronto; (Drs. Hux, Juurlink, Alter) Department of
Health Policy, Management and Evaluation, University of Toronto;
(Dr.Lipscombe) Women's College Hospital; (Drs. Hux, Juurlink) Sunnybrook
Health Sciences Centre; Toronto, Ontario; (Ms. Levesque) Dept. of Community
Health and Epidemiology, Queen's University; (Ms. Levesque) Kingston, Lennox,
Frontenac& Addington (KFL&A) Public Health, Kingston, Ontario. The authors
have no conflict of interest to declare.
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:
For further information: MEDIA CONTACT, Kristine Galka, Media Advisor,
ICES, Office: (416) 480-4780, Cell: (416) 629-8493, Email: