PITTSBURGH, Aug. 23 -- People with Type 1 diabetes develop heart disease at more than five times the rate of the general population, making it the leading cause of death among these patients. Researchers at the University of Pittsburgh Graduate School of Public Health (GSPH) and the University of Pittsburgh Medical Center (UPMC) Cardiovascular Institute have found that a fast, non-invasive heart scan using electron beam computed tomography (EBT) may be an important tool in identifying Type 1 diabetic patients who are at a particularly high risk for heart disease. Their findings were published in the September issue of Diabetes, a journal of the American Diabetes Association.
"Finding a way to identify high-risk subjects early is critical in preventing the high mortality and suffering that many Type 1 diabetic patients endure from heart disease," said Trevor Orchard, M.D., professor of epidemiology at GSPH and the study's principal investigator.
EBT is a quick, simple scan used to identify and measure calcium build-up in the arteries leading to the heart. This build-up is seen in individuals with developing blockages in the coronary arteries, some of which may eventually lead to angina and heart attack.
The University of Pittsburgh study is the first to report the use of EBT to identify people with Type 1 diabetes at high risk for heart disease. Risk is normally measured using well-known risk factors such as blood pressure and cholesterol readings, and information on health behaviors like smoking.
"EBT provides an excellent measure of atherosclerotic burden in the coronary arteries," said Daniel Edmundowicz, M.D., assistant professor of medicine, director of the Preventive Heart Care Center at the UPMC Cardiovascular Institute and study co-investigator. "We believe the test will identify some diabetics as higher risk than might be thought based on traditional risk factors. If so, they could be identified much earlier in their coronary artery disease process, giving us more time to lower their risk with medications and lifestyle changes, and possibly other interventions."
Type 1 diabetes, sometimes called "juvenile diabetes," typically strikes in childhood when the pancreas cannot make insulin, a hormone that helps glucose enter cells so that it can be used for energy. Type 1 diabetic patients must take regular insulin injections.
The current analysis used data from the Pittsburgh Epidemiology of Diabetes Complications Study, an ongoing 10-year prospective study of risk factors for complications of Type 1 diabetes. More than 300 participants, all diagnosed as children, had the EBT, and their resulting calcium scores were compared with other risk factors and their history of heart disease.
"Because patients with Type 1 diabetes might develop extra calcium in their arteries that is not related to atherosclerosis, we were uncertain how well the test would identify subclinical heart disease in these patients," said lead author Jon Olson, Ph.D., of the GSPH. "However, we found a strong association between high calcium scores and heart disease, and also between high calcium scores and the standard risk factors. These relationships suggest that the high scores do indeed indicate atherosclerosis."
Investigators consider the collection of these data to be the first step in evaluating the EBT's usefulness in identifying those patients who are at highest risk. They will continue monitoring the study participants for further signs of heart disease to determine if the EBT predicts better than the standard risk factors.
"It is too soon to suggest that all Type 1 diabetic patients have an EBT, which in any case is not widely available," said Dr. Orchard. "However, it remains extremely important that diabetic patients keep in close touch with their physicians and carefully monitor their blood pressure and lipids. These factors must be strictly controlled."
This study was supported by the National Institutes of Health.
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