NEW ORLEANS — There were no differences in total mortality among patients with type 2 diabetes and stable coronary heart disease who underwent early coronary revascularization compared with those who underwent intensive medical therapy alone, results from a large 5-year trial showed.
However, those who underwent coronary artery bypass grafting (CABG) had significantly lower rates of major cardiovascular events compared with medical therapy alone, an association that was not seen among those who underwent percutaneous coronary intervention (PCI).
In addition, the Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI 2D), which also studied two glucose-lowering strategies, found no difference in outcome whether the patients received insulin-providing or insulin-sensitizing therapy.
The trial results were presented by Dr. Trevor J. Orchard at the annual scientific sessions of the American Diabetes Association.
“I don't think our results will change [clinical] practice, except to reassure clinicians and patients alike that treatment with insulin sensitizers is a perfectly safe and reasonable approach,” Dr. Orchard, professor of epidemiology at the University of Pittsburgh Graduate School of Public Health, said during a press briefing about the study.
BARI 2D is the first randomized study conducted in patients with mild symptoms and stable ischemic heart disease to show a benefit of CABG in reducing major cardiovascular events, “which were primarily nonfatal myocardial infarction,” said cardiologist Robert L. Frye, chair of the trial and professor of cardiovascular medicine at the Mayo Clinic in Rochester, Minn.
During January 2001-March 2005, researchers in six countries enrolled 2,368 patients with type 2 diabetes and stable coronary artery disease who were candidates for elective PCI or CABG. Each patient was selected to either a CABG stratum group or to a PCI stratum group (N. Engl. J. Med. 2009;360:2503-15).
Of the 763 patients in the CABG stratum group, 385 were randomly assigned to medical therapy (194 to insulin provision and 191 to insulin sensitization) and 378 were randomly assigned to revascularization with CABG, with 190 and 188 assigned to receive insulin provision and sensitization, respectively.
Of the 1,605 patients in the PCI stratum group, 807 were randomly assigned to medical therapy (399 to insulin provision and 408 to insulin sensitization) and 798 were randomly assigned to revascularization with PCI, with 402 and 396 assigned to receive insulin provision and sensitization, respectively.
The study's primary end points were the rate of death and the rate of major cardiovascular events, defined as a composite of death, myocardial infarction, or stroke.
At the time of study entry, the mean age of patients was 64 years, 70% were male, and 66% were white. Mean HbA1c level was 7.7% and mean duration of diabetes was 10 years.
Dr. Orchard reported that at 5 years, there were no statistically significant differences in the rates of survival between the revascularization group and the medical therapy group (88.3% vs. 87.8%, respectively) nor between the insulin-sensitization group and the insulin-provision group (88.2% vs. 87.9%).
There also were no differences in the rates of freedom from major cardiovascular events between the revascularization group and the medical therapy group (77.2% vs. 75.9%, respectively) nor between the insulin-sensitization and insulin-provision groups (77.7% vs. 75.4%).
When the researchers analyzed data from the PCI stratum alone, they observed no statistically significant differences in the primary end points between the revascularization group and the medical therapy group.
However, when they analyzed data from the CABG stratum alone, the rate of major cardiovascular events was significantly lower in the revascularization group compared with the medical therapy group (22.4% vs. 30.5%, respectively). This benefit appeared to be greatest in those who underwent CABG and received insulin-sensitizing drugs.
The BARI 2D was supported by grants from the National Heart, Lung, and Blood Institute and the National Institute of Diabetes and Digestive and Kidney Diseases. Support was also provided by GlaxoSmithKline, Lantheus Medical Imaging, Astellas Pharma, Merck, Abbott Laboratories, Pfizer, MediSense, Bayer, Becton Dickinson, J.R. Carlson Labs, Centocor, Eli Lilly & Co., LipoScience, Novartis, and Novo Nordisk. Dr. Orchard has served on advisory boards and received consulting fees from several companies that make diabetes-related pharmaceuticals and products, and has an equity interest in Bristol-Myers-Squibb. Dr. Frye is on the advisory boards of Sanofi-Aventis and Schering-Plough.
Mortality was similar, but CABG had lower rates of major cardiovascular events than medical therapy. DR. ORCHARD