SUNDAY, June 8 (HealthDay News) -- Older adults with type 2 diabetes run much less risk than previously believed of having silent myocardial ischemia, a restriction of blood flow to the heart, according to a new study.

In fact, all adults aged 55 to 75 with type 2 diabetes run the same risk of having a cardiac condition whether they are screened for the problem or not, based on findings expected to be presented June 9 in San Francisco at the American Diabetes Association's Annual Scientific Sessions.

Some past studies had suggested as many as 60 percent of adults with diabetes run the risk of silent myocardial ischemia, which occurs without the typical prior warning signs such as chest pain (angina). Since it is common for people with diabetes to have neuropathy, a type of nerve damage, it was though many of them wouldn't feel any warning pain or it wouldn't feel strong enough to the diabetic to send him or her to a doctor.

Study participants, evaluated over five years, consisted of 1,123 adults with type 2 diabetes in the United States and Canada who had no previous cardiac symptoms, diagnosis of coronary artery disease, and normal electrocardiograms.

"We found that silent myocardial ischemia -- restriction of blood flow to the heart -- occurred in only 22 percent of the asymptomatic adults with type 2 diabetes that we screened, a far lower percentage than expected," study leader Dr. Frans J. Wackers, professor emeritus of Diagnostic Radiology and Medicine at the Yale University School of Medicine, said in a prepared statement.

His study also concluded that this lower prevalence of ischemia did not justify putting all people with type 2 diabetes through expensive coronary artery disease screening.

The rate of cardiac events, the study determined, was a half percent per year, much lower than expected. Wackers attributed some of this good news to the cardiac procedures, such as bypass surgery, undertaken by the small group of ischemic patients regardless of whether or not they were in a group specifically screened for the silent medical condition.

"Over the course of the study, all participants continued to be seen by their own physicians, and the physicians of 30 percent of the unscreened control group independently found reason to recommend various diagnostic and treatment procedures, such as stress testing, cardiac catheterization, angioplasty, and bypass surgery, to their patients," Wackers said. "Since these control patients likely had an equal prevalence of ischemia to those who were screened, standard clinical care and attentive follow-up appear to be sufficient to detect those at risk and in need of intensive cardiologic care."

About 65 percent of diabetics die from heart disease or stroke, according to U.S. National Institutes of Health statistics. Adults with diabetes have heart disease at a rate two to four times higher than those without diabetes.

Almost 21 million Americans have diabetes, a condition resulting from high blood glucose levels that cause the body to be unable to produce or use insulin. It is the fifth leading cause of death by disease in the United States. Type 2 most often occurs in adults who are overweight and aged 40 and older.

More information

The American Heart Association has more about ischemia.

-- Kevin McKeever

SOURCE: American Diabetes Association, news release, June 6, 2008

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