The Nation - News from June 8, 2009
For most patients with diabetes and clogged arteries who have not had a heart attack, treatment with drugs and lifestyle changes are as effective at reducing the risk of death as immediate bypass surgery or angioplasty, researchers said Sunday.
For diabetics with a more severe form of heart disease requiring immediate surgery, bypass surgery is more effective than angioplasty at reducing risk of heart attacks and strokes, but not deaths, researchers reported at a meeting of the American Diabetes Assn. in New Orleans.
The findings are a second major blow to companies that manufacture the stents that are inserted into arteries after angioplasty to keep them open, a process that is performed at least 1.24 million times each year in the U.S. A 2007 study of nondiabetics also found that drug treatment and lifestyle changes were as effective as angioplasty in preventing deaths.
In this era of healthcare reform, “some may legitimately question . . . why we continue to do so many [angioplasty] procedures,” wrote Dr. William E. Boden of the University of Buffalo in an editorial accompanying a paper on the results to be published this week in the New England Journal of Medicine.
For controlling diabetes, the new study found that drugs that increase insulin levels are as effective as those that increase the body’s sensitivity to insulin and that no significant side effects are associated with either approach.
That is good news for Glaxo- SmithKline, manufacturer of the insulin-sensitizing drug Avandia, which has been linked to an increased risk of heart problems in some studies.
“The insulin sensitization drugs are not harmful . . . and may be a little better,” said Dr. Trevor Orchard of the University of Pittsburgh, who led the study.
The patients who received them “didn’t gain as much weight, had less hypoglycemia and it was easier for them to get control” of their diabetes, he said in a news conference.
Experts noted, however, that the study covered only a relatively narrow range of patients -- those whose cardiovascular disease is largely asymptomatic. For those with severe blockage and strong symptoms, “medical therapy is not enough, and revascularization [surgically reopening arteries] may be a safe and effective option for improving their quality of life,” said Dr. Steven R. Bailey of the University of Texas Health Science Center at San Antonio, president of the Society for Cardiovascular Angiography and Interventions.
Critics also noted that most of the patients were treated before newer, drug-eluting stents came into common use. Drugs released from such stents help prevent arteries from reclosing.
“The standard of care has evolved since [the study] was initiated and many of the early patients in the trial did not receive the care we now know to be most effective,” Bailey said.
As obesity has increased in the U.S., diabetes has reached near-epidemic levels. About 24 million people are afflicted, most of them with Type 2, or adult-onset, diabetes. Cardiovascular disease is one of the most common side effects of diabetes: About 65% of diabetics die from heart disease or stroke.
The new study, called BARI-2D, was begun in 2001 to test ways of controlling both diabetes and heart disease. Researchers enrolled 2,368 patients at 49 centers in six countries. For diabetics, heart attacks typically occur earlier in life and are more often fatal.
One component of the study compared prompt surgical treatment of blocked arteries to intensive medical treatment. The second compared drugs that increase insulin availability with those that increase the body’s sensitivity to insulin. Patients were followed for an average of five years.
The team found that 88.3% of patients in the revascularization group survived for five years, compared with 87.8% in the medical treatment group. About 40% of those in the medical treatment group eventually required revascularization.
“But that means 60% never required revascularization,” which is expensive and potentially dangerous, said Dr. Robert L. Frye of the Mayo Clinic College of Medicine, one of the report’s authors.
They also found that 87.9% of those receiving insulin or insulin-stimulating drugs survived for five years, compared with 88.2% of those receiving insulin-sensitizing drugs such as Avandia.
The only significant difference observed between the groups was that 22.4% of patients receiving bypass surgery had heart attacks or strokes or died, compared with 30.5% of those who received drug therapy alone. In this group, the benefit was greatest in those who received insulin-sensitizing drugs. But the study was not designed to consider that, so more work will be required to determine how important this finding was.
“BARI-2D is a spectacular, seminal study,” said Dr. Kirk Garratt of Lenox Hill Hospital in New York, who was not involved in the research. “Diabetic people are at greater risk of dying, so being more aggressive with them is appealing. BARI-2D tells us that neither open-heart surgery nor balloon angioplasty lowers that risk, despite the appeal. . . . Diabetic patients with the worst coronary disease may be considered for an operation, but they should no longer be told that getting open heart surgery will save their lives.”
The study was sponsored by the National Institutes of Health and several pharmaceutical companies.
Most of the authors have received consulting fees from the companies.
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