Heart Screening Not Effective for Type 2 Diabetics
Imaging test doesn't single out those at high risk of trouble, study found
TUESDAY, April 14, 2009 (HealthDay News) -- Routine screening for coronary artery disease is of no value for adults with diabetes who have no symptoms of heart problems, a new study finds.
Screening is expensive, at $1,000 per test. But the study of 1,123 people with type 2 diabetes who had no symptoms of heart disease did not identify those at high risk of developing cardiac problems.
The findings were published in the April 15 issue of the Journal of the American Medical Association -- an issue devoted to diabetes.
"It was a surprise," Dr. Lawrence H. Young, professor of medicine at Yale University and a leader of the study, said of the results. "There is no question that coronary artery disease is still a major concern in patients with type 2 diabetes."
While the study did identify a small group of people at increased risk of coronary artery disease, "in the overall population, patients who were screened did not have a better outcome specifically in terms of heart attacks and cardiac death," Young said.
For doctors managing people with type 2 diabetes, "the implication is that a routine patient who is doing well, on state-of-the-art medication such as cholesterol-lowering drugs, aspirin and diabetes therapy, need not be subjected to specialized stress testing," he said. "But patients who have any symptoms of heart disease need to be screened."
The people in the study were randomly assigned to have either a sophisticated screening test -- adenosine-stress radionuclide myocardial perfusion imaging -- or no test. In a follow-up period averaging 4.8 years, 2.7 percent of the people in the screened group had heart attacks or died of cardiac disease, compared to 3.0 percent of those who were not screened.
Many of the people in the study had well-known risk factors for heart disease, Young noted. "In our study, most patients were overweight, and many had other risk factors such as hypertension [high blood pressure] and high cholesterol," he said. "But those were treated well by the primary-care physicians."
Diabetics who should be screened are those with a family history of heart disease or have symptoms of cardiac problems, such as the chest pain called angina, feeling of tightness and heaviness in the chest, and unexplained shortness of breath on exertion, Young said.
One possible reason for the negative finding in the study is that plans for the trial were made eight or nine years ago, and preventive measures have improved since then, said Dr. Steven D. Wittlin, professor of medicine at the University of Rochester in New York, and a member of the study group. The incidence of heart problems found in the study was lower than had been expected, he said.
"During that time, a lot more people have gone on aspirin and ACE inhibitors and other drugs, and that may account for the low rate," Wittlin said.
There are two major findings in the study, he said. "On the one hand, it verifies that people with type 2 diabetes who are middle-aged and have a positive stress test have an increased risk of a cardiac event," Wittlin said. "But the event rate was low enough so that it does not appear to be cost-effective to routinely screen patients with a nuclear stress test."
The American Heart Association describes the role of diabetes in heart disease.