June 15, 2009

Treatment Options for Those with Diabetes and Heart Disease

Photo of an older man and a physician

For most patients with diabetes and stable heart disease, intensive drug therapy is as effective as prompt surgery in preventing death, heart attack and stroke, according to a large clinical study. But in a subset of patients with more severe artery blockage, prompt bypass surgery seems best for reducing major cardiovascular risks.

A growing number of Americans, about 23.6 million, have diabetes. The high blood sugar levels seen with diabetes can lead to serious health problems, including heart attack and stroke. In fact, about 65% of those with diabetes die from cardiovascular disease.

Several treatment options are available for patients who have stable coronary artery disease, a blockage of the arteries that feed the heart. The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) study was funded by NIH's National Heart, Lung and Blood Institute (NHLBI), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and several pharmaceutical companies to compare optimal medical therapy, including medications and lifestyle changes, with surgical approaches in patients who have both diabetes and coronary artery disease.

The study enrolled 2,368 adults with both type 2 diabetes and stable coronary artery disease that did not require immediate intervention. All were considered candidates for elective surgery to improve blood flow to the heart. Physicians divided them into 2 groups based on the extent of coronary blockage.

The first group, about one-third of the patients, had more serious blockage and so were considered more likely to benefit from coronary bypass surgery. The remaining 1,605 patients were deemed better suited for a less-invasive surgery called angioplasty, which often involves placing a tiny wire-mesh tube, or stent, in the coronary artery. About half of patients in each group were then were randomly assigned to either promptly receive the recommended surgery along with optimal medical therapy, or to receive optimal medical therapy alone.

The results were published online on June 7, 2009, in the New England Journal of Medicine. After about 5 years of followup, the researchers found that death rates were about 12% in both the surgery and the medical therapy groups. Both groups also had similar rates of major cardiac events—either death or nonfatal heart attack or stroke.

However, a significant difference was seen in the subgroup of patients who were pre-identified as candidates for coronary bypass surgery. Of those who received surgery within the study's first month, 22% later had a major cardiac event, compared to 30% of those who initially received optimal medical therapy alone.

Another arm of the study looked at diabetes control. The researchers found that, overall, therapies using insulin-sensitizing drugs are as effective insulin-providing drugs in reducing death rates and major cardiovascular events.

“Overall, the BARI 2D results reassure us that our current major drug treatments for diabetes are equally appropriate,” says study coauthor Dr. Saul Genuth of Case Western Reserve University. “They also indicate that when a patient with type 2 diabetes has more severe heart disease, it may be better to do bypass surgery early than to wait and simply treat with medication. For patients with milder disease who are candidates for angioplasty, it is appropriate to treat with drug therapy first.”

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