The results show that such patients were no more likely to die or to have a heart attack or stroke over a five-year period if they took medications to control blood sugar, blood pressure, and cholesterol levels than if they underwent prompt bypass surgery or angioplasty with or without stents.
But for some patients, immediate bypass surgery may cut the risk of heart attacks, the study shows.
Results also suggest that diabetes drugs that lower the body's resistance to insulin, such as metformin, Avandia, and Actos, work just as well and are just as safe as drugs that increase the amount of insulin in the body.
"This should provide reassurance to patients," since some studies have suggested that drugs like Avandia may be harmful to the heart, says researcher Trevor Orchard, MD, of the University of Pittsburgh Graduate School of Public Health.
The study was presented at the American Diabetes Association (ADA) 69th Scientific Sessions in New Orleans and simultaneously published in The New England Journal of Medicine.
The results do not apply to people who get bypass surgery or angioplasty because they are in the midst of a heart attack or whose chest pain or other symptoms suddenly gets worse, doctors stress. For them, prompt intervention to open or bypass clogged arteries is a proven lifesaver.
Comparing Drug Therapy and Surgery
Two years ago, another study showed that angioplasty plus stents are no better than drug treatment at preventing heart attacks and death in people who do not have diabetes.
The new study aimed to find the best way to treat people with type 2 diabetes and heart disease, which Orchard calls "the deadly duo."
More than 20 million Americans have type 2 diabetes, which involves the body's inability to properly use its own insulin and occurs mainly in adults who are overweight and 40 and older. More than 65% of deaths in people with diabetes are due to heart disease or stroke.
The study involved 2,368 patients with type 2 diabetes and stable coronary artery disease who were under a doctor's care to control their cholesterol and blood pressure.
Patients were randomly assigned to receive drug therapy plus undergo prompt bypass surgery or angioplasty (with or without stents) to open blocked arteries, or to receive drug therapy alone. Then, they were randomly assigned to one of two strategies to control blood sugar: insulin-providing drugs like insulin injections or sulfonylureas that increase the body's production of insulin, or insulin-sensitizing drugs like metformin or a class of drugs known as glitazones, which includes Avandia and Actos.
Orchard stresses that the study was not a comparison between angioplasty and bypass surgery, but rather a comparison between a prompt procedure and medical therapy alone.
Among the findings:
- A total of 88.3% of people who got angioplasty or bypass were alive five years later, compared with 87.8% who got drug treatment, a difference so small it was due to chance.
- There was no significant difference in the five-year survival rate among people who got insulin-providing drugs (87.9%) and those who received insulin-sensitizing drugs (88.2%).
- The five-year rate of heart attacks, strokes, and death was similar among patients who received angioplasty, with our without stents, and those who received drug therapy alone.
- The five-year rate of heart attacks, strokes, and death was significantly lower among patients who received bypass surgery (22.4%), compared with those who received drug therapy alone (30.5%). This benefit was largely driven by a reduction in heart attacks in patients who were treated with insulin-sensitizing drugs, Orchard tells WebMD.
- Adverse events were generally similar among patients who received insulin-providing and insulin-sensitizing diabetes drugs, "although there seemed to be a little less weight gain and hypoglycemia" among those who took insulin-sensitizing agents, he adds.
Getting Care From a Team of Doctors
Richard Bergenstal, MD, president-elect of medicine and science at the ADA and executive director of the International Diabetes Center in Minneapolis, Minn., says the study shows that aggressive and simultaneous management of blood pressure, blood cholesterol, and blood sugar works.
His advice to people with diabetes: "Be sure you work with a team of doctors who address all three of these factors. The team should include not just a diabetes doctor, but a primary care physician and heart doctor."
Also, be sure to tell your doctor about any new symptoms such as chest pain or breathlessness, so the physician can ensure you get bypass surgery if needed, Bergenstal tells WebMD.
Many people with diabetes do not suffer the typical chest pain of angina, says researcher Robert Frye, MD, a cardiologist at the Mayo Clinic in Rochester, Minn. "Unusual breathlessness may be the only symptom," he says.