Heart disease is the top killer of people with diabetes, and diabetics represent one-quarter of all patients who undergo coronary artery procedures.
Patients and their doctors face a choice between doing more invasive coronary artery bypass surgery or using balloons and stents (small mesh tubes) to widen the narrowed arteries.
In Thursday's online issue of the journal Lancet Diabetes and Endocrinology, cardiac surgeons and cardiologists reviewed randomized controlled trials comparing the two types of procedures in adults with diabetes and multiple blockages.
"The important message here is that there is at least one-third reduction in mortality from any cause if people with diabetes have bypass surgery over having angioplasty with a stent," said Dr. Subodh Verma, a cardiac surgeon at St. Michael's Hospital and the principal author of the paper.
In previous studies, mortality statistics weren't as clear. But it's the outcome that trumps all others in cardiovascular trials, Verma said.
Although patients with diabetes did better with bypass surgery, the procedure was associated with an increased risk of non-fatal strokes, which the researchers said may be linked to stopping the heart during surgery.
Since the observations don't apply to every patient with diabetes, a physician should work with each patient to determine the best choice, Verma said.
The European Society of Cardiology has proposed that such patients with diabetes receive a joint decision-making approach to their treatment including both cardiologists who perform angioplasty and stent procedures and cardiac surgeons who do bypass surgery.
Despite guidelines in the U.S. that recommend bypass surgery in people with diabetes and multivessel disease, the researchers said the findings will be difficult to put into practice in Canada "until joint decision making between a cardiologist and cardiac surgeon is facilitated."
Dr. Anthony Glanz is a cardiologist at Hotel Dieu Hospital in Windsor who does angiograms but not stents. He reviewed the research, which he called compelling.
It's tempting to put in stents immediately for people with diabetes but the findings show it's worth pausing and involving cardiac surgeons and others when the patient is stable, Glanz agreed.
Ronald Martin of Newcastle, Ont., 80 kilometres east of Toronto, was never offered stents because his condition was so dire. After his family doctor was concerned about his shortness of breath, swollen feet and high blood pressure during a checkup, an angiogram was ordered and showed serious blockages. The 66-year-old diabetic needed an immediate triple bypass at St. Michael's.
"My health is better than it's been for a long time," said Martin, who now walks nearly five kilometres a day in addition to 30 minutes of aqua fitness. "There's no greater motivator than your own mortality."
About 2.4 million Canadians have been diagnosed with diabetes, according to the Public Health Agency of Canada.
The research was funded by the Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada and Canada Research Chairs program.