Diabetes with coronary disease: A moving target amid evolving therapies

Jun 8 2009

In an editorial in the current issue of the New England Journal of Medicine (NEJM), William E. Boden, M.D., professor of medicine and preventive medicine at the University at Buffalo, recommends that the results of the BARI-2D Trial published in that edition must be interpreted with "considerable caution."

The editorial is titled "Diabetes with Coronary Disease -- A Moving Target Amid Evolving Therapies?"

Boden bases his cautionary note on the fact that the trial did not meet its primary end point of long-term mortality reduction with myocardial revascularization, as compared with optimal medical therapy.

In addition, he notes in the editorial that an important trial secondary outcome -- freedom from death, heart attack or stroke -- did reveal new and important information that reaffirms the potential long-term benefit associated with coronary artery bypass graft (CABG) surgery for treating diabetic patients with coronary artery disease.

Boden is clinical chief of the UB Division of Cardiovascular Medicine in the UB schools of Medicine and Biomedical Sciences and Public Health and Health Professions, and Kaleida Health's medical director of cardiovascular services and chief of cardiology at Buffalo General Hospital and Millard Fillmore Hospitals.

In the editorial Boden states: "The BARI-2D results replicate the principal finding of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial -- that an initial strategy of PCI [percutaneous coronary intervention -- stenting and/or balloon angioplasty] provides no incremental clinical benefit over intensive medical therapy, including in patients with both diabetes and coronary disease."

The BARI-2D trial set out to test two heart management strategies and scientific hypotheses: that prompt revascularization with either PCI or coronary-artery bypass grafting would be superior to optimal medical therapy alone; and that increasing patients' sensitivity to insulin produced by the pancreas would be superior to insulin injections.

The trial results were presented at the American Diabetes Association annual meeting June 7 in New Orleans and published simultaneously online. The paper and editorial will appear in print in the June 11, 2009, issue of the journal.

Boden was the lead investigator and study chairman of the COURAGE trial, a study of almost 2,300 chronic stable angina patients randomized to optimal medical therapy with or without PCI.

This landmark clinical trial, published in the NEJM in 2007, showed that optimal medical therapy alone was just as effective in preventing death, a heart attack or other major cardiovascular events in patients with stable heart disease as coronary revascularization with stenting or balloon angioplasty combined with optimal medical therapy during an average 4.6 year follow-up period.

The results of COURAGE have reverberated worldwide over the past 2 years, Boden noted, as many physicians increasingly have turned to aggressive medical therapy and lifestyle intervention as an equally effective initial approach to patient management.

"The COURAGE trial results have sparked intense debate within the cardiology community," Boden noted, "particularly among many interventional cardiologists who have suggested that 'clinical practice should not change based on the results of only one research trial.'

"The BARI-2D trial found that there was no incremental benefit of PCI on top of a background of optimal medical therapy in 2,368 patients with coronary disease and established diabetes (average duration: 10 years)," commented Boden.

"BARI-2D likewise replicates the earlier findings of the original BARI trial -- that patients who underwent CABG fared better than those who underwent balloon angioplasty, especially in patients with diabetes and multi-vessel coronary artery disease.

"The important findings of the BARI-2D trial, combined with a recent authoritative review of 10 randomized trials comparing PCI with CABG surgery, show that diabetics derive an important survival advantage and a reduced rate of subsequent heart attack with CABG surgery, while PCI was not associated with any such benefit," he said.

"The continued high rate of use of PCI (1.24 million procedures per year in the U.S.) and the high rate of drug-eluting stent usage strongly suggests that we critically reassess our approach to revascularization, if needed, in diabetics with coronary disease."

He continued: "Some may legitimately question, based on the BARI-2D trial results, why we continue to do so many PCI procedures in patients, especially diabetic patients with extensive multi-vessel coronary disease, whose clinical outcomes would appear to be significantly enhanced by CABG surgery?"

Boden speculates that in this era of mounting health care reform, physicians, payers and health economists will begin to scrutinize more carefully the level of clinical evidence that supports and guides clinical treatment decisions.

"The interventional community will continue to support PCI because it does result in symptom improvement," he said. "But, if faced with a decision of needing revascularization, it would seem logical, if not preferable, that patients and referring physicians would increasingly base treatment decisions on the scientific evidence that supports clinical superiority, and on approaches that improve hard outcomes (i.e., death, MI, etc.) and not just a relief of angina symptoms, especially in diabetic patients with more extensive coronary disease who may require revascularization."

The University at Buffalo is a premier research-intensive public university, a flagship institution in the State University of New York system and its largest and most comprehensive campus. UB's more than 28,000 students pursue their academic interests through more than 300 undergraduate, graduate and professional degree programs. Founded in 1846, the University at Buffalo is a member of the Association of American Universities.