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BARI 2D: Revascularization no more beneficial than intensive medical therapy in diabetes, CAD
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American Diabetes Association's 69th Scientific Sessions
The much anticipated results of the Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI 2D) trial indicate no significant advantage of prompt revascularization over intensive medical therapy on mortality and major cardiovascular events in patients with type 2 diabetes and stable coronary artery disease.
At five years, there was no difference in the primary outcome – rate of death – between patients randomly assigned to revascularization (88.3%) – percutaneous coronary intervention or coronary artery bypass graft surgery – compared with intensive medical therapy alone (87.8%; P=.97). Rates of survival were also similar between patients assigned to insulin sensitization (88.2%) vs. insulin provision therapy (87.9%; P=.89).
Prompt revascularization also had no benefit on freedom from major CV events (composite of death, myocardial infarction or death), another primary outcome, compared with intensive therapy (77.2% vs. 75.9%; P=.70). Similarly, there was no significant difference in the insulin sensitization (77.7%) and insulin provision groups (75.4%; P=.13).
“BARI 2D has shown that neither prompt revascularization vs. delayed revascularization or insulin sensitization vs. insulin provision was superior in terms of mortality,” Trevor Orchard, MD, professor of epidemiology, University of Pittsburgh Graduate School of Public Health. Orchard and colleagues presented the data today at the American Diabetes Association’s 69th Scientific Sessions.
PCI alone vs. medical therapy showed no differences in rate of death or CV events. Yet, prompt CABG, compared with medical therapy alone, yielded significantly better outcomes when major CV events were considered in addition to death (22.4% vs. 30.5%; P=.01), according to Orchard. Much of this benefit with CABG was an observed reduction in nonfatal MI, which has never before been shown this intervention (7.4% vs. 14.6%).
The data build on that from the first BARI trial, which was published in 1996 and compared CABG and PCI using balloon angioplasty in patients with CAD. Results demonstrated no difference in long-term mortality rate and MI; however, results indicated slightly better survival after CABG among patients with diabetes.
The BARI 2D researchers cautioned that the trial did not compare CABG and PCI; however, “the differences in secondary end points render indirect comparisons likely,” William E. Boden, MD, and David P. Taggart, MD, PhD, wrote in a New England Journal of Medicine editorial.
Another comparison is BARI 2D to the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial. “The BARI 2D results replicate the principal finding of the COURAGE trial – that an initial strategy of PCI provides no incremental clinical benefit over intensive medical therapy,” Boden and Taggart wrote.
Randomized trial of therapies for diabetes, CAD
BARI 2D compared both a CV treatment approach and diabetes control approach in 2,368 patients with type 2 diabetes and CAD. Patients were randomly assigned to prompt revascularization or intensive medical therapy alone, per the referring physician’s recommendation. Patients assigned to revascularization underwent the procedure within four weeks of randomization; patients assigned to medical therapy alone underwent revascularization only following reports of angina, acute coronary syndrome or severe ischemia.
A second component of the study compared whether controlling diabetes with insulin-sensitizing drugs (metformin and thiazolidinediones) had an advantage over insulin-providing drugs (insulin, sulfonylureas), and the same patient population was randomly assigned to one of the two treatment arms.
Of note, all patients were treated to a target HbA1c of <7%, LDL <100 mg/dL and BP <130/80 mm Hg. Patients also received lifestyle counseling for smoking cessation, weight loss and exercise.
“The intent was to determine if prompt revascularization would reduce event rates vs. simply treating them medically,” Robert L. Frye, MD, of the Mayo Clinic, said in the press conference.
In contrast to previous reports, the researchers observed no increase in MI among patients in the insulin-sensitizing group who received rosiglitazone (Avandia, GlaxoSmithKline).
Additionally, the “benefit of prompt bypass surgery appears to be particularly strong among those treated with insulin-sensitizers,” Orchard said.
Safety analysis revealed similar adverse events among the groups. One difference was greater frequency of severe hypoglycemia in the insulin-provision group (9.2%) compared with the insulin-sensitization group (5.9%; P=.003). Less weight gain and higher HDL were reported with insulin-sensitizing drugs.
Two viewpoints
“From the diabetes viewpoint, we are assured that treatment with insulin-sensitizing drugs, which have been a concern in the past, are not harmful and this is a perfectly reasonable alternative to diabetes management, Orchard said.
“From the cardiology perspective, the most striking finding was the identification of a high-risk group of patients who were selected for CABG and had the most extensive CAD who benefited from prompt CABG. It is the first demonstration in a properly conducted randomized trial that CABG reduces nonfatal MI,” Frye said.
The finding “emphasizes the important of continuing what has been a long-time effort,” he added.
The researchers concluded that the findings of BARI 2D and those of COURAGE provide evidence that “one can start safety with an initial program of medical therapy,” Frye said. – by Katie Kalvaitis
I am impressed with the results. The message is to encourage patients to continue lifestyle habits that support them so they don’t have to go to the step of having surgery, hopefully. [The data] reinforce how much patients need to know about the current status of their disease. Just from a lifestyle standpoint, no matter what we have as advances in surgeries or medications it is always important [that patients] continue to exercise and eat healthy and talk about things like what is safe for exercise with the physician. Even though we have these wonderful treatments, unfortunately, there are some lifestyle choices that can be made that won’t help keep [patients healthy].
- Susan McLaughlin, CDE, RD
President, Health Care and Education, ADA