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Increase in the number of diabetics negates gains from reduced cardiovascular complications

December 22, 2005 Toronto

A new study from the Institute for Clinical Evaluative Sciences (ICES) has found that, although Ontarians with diabetes are at lower risk of developing a heart attack or stroke today than they were 10 or 15 years ago, the dramatic growth of diabetes in the population has driven up the overall numbers of people with heart disease in the province.

Projections estimate that the number of people affected by diabetes in Canada and the United States will double in the next 20 years. “Since one-third of all heart attacks and strokes occur in people with diabetes, it is essential that we consider diabetes when looking to reduce overall rates of heart disease,” said study lead author and ICES adjunct scientist Dr. Gillian Booth.

“The last decade has seen tremendous advances in the treatment of heart disease risk factors. However, earlier studies suggested that people with diabetes had benefited less from these medical advances than those without this disease.”

To conduct the study, ICES scientists identified over 670,000 Ontario adults with diabetes and more than nine million adults without diabetes between 1992 and 2000. Changes in the numbers of people admitted to hospital for heart attack and stroke, as well as changes in the numbers of people who died from heart attack, stroke and all causes, were compared between those with and without diabetes.

Results:

  • Over the study period, the rate of persons admitted to hospital for heart attack and stroke fell to a greater extent in the diabetic than the non-diabetic population (heart attack: -15.1 vs. –9.1%; stroke -24.2% vs. -19.4%).
  • Diabetic patients experienced similar reductions in mortality rates related to heart attack and stroke to those without diabetes (-44.1% vs. –33.2%; -17.1% vs. –16.6%, respectively). Declines in all-cause mortality were also comparable in the two populations.
  • The number of diabetes cases over the study period increased from 405,471 to 670,602. Thus, while heart disease and associated mortality rates fell, the overall number of cardiovascular events occurring in the Ontario population rose substantially because of the increase in diabetes cases (heart attack: +44.6%; stroke: +26.1%; heart attack deaths: +17.2%; stroke deaths: +13.2%).

“The fact that diabetes patients in Ontario are seeing reductions in cardiovascular complications is encouraging, and most likely a reflection of improvements in prevention strategies both before and after having a heart attack,” said Dr. Booth.

“However, we have to start focusing on preventing diabetes itself in order to avoid a further rise in the overall burden of heart disease on our health care system and society.”

The study, “Recent trends in cardiovascular complications among men and women with and without diabetes”, is in the January 2006 issue of Diabetes Care.

Author affiliations: ICES (all authors); Department of Medicine (Drs. Booth, Kapral, and Tu) University of Toronto; St. Michael’s Hospital (Dr. Booth); Sunnybrook and Women’s College Health Sciences Centre (Dr. Tu); University Health Network Women’s Health Program (Dr. Kapral).

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:

  • Julie Dowdie
  • Media Relations Officer, ICES
  • (416) 480-4780 or cell (416) 432-8143

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