Impact of various diabetes treatments on patients' health after heart attack.

Mayo Clinic researchers helped clarify a growing concern about the link between diabetes mellitus treatments and heart attack with the first large, population-based study showing that a group of common medications does not reduce diabetic patients' heart attack survival rates.

These results were presented today at the American Heart Association's Scientific Sessions 2007 in Orlando, Fla.

The drugs studied are called sulfonylureas and include several commonly used pills to increase insulin release to lower blood sugar. Second-generation sulfonylureas -- known collectively as SU2 -- include glimepiride (Amaryl), glipizide (Glucotrol, Glucotrol XL), and glyburide (DiaBeta, Micronase, Glynase).(1)

Significance of the Mayo Clinic Study

The prevalence of diabetes mellitus is growing rapidly, and physicians need evidence for their treatment recommendations. Worldwide, the number of diabetics is projected to more than double in three decades, from 171 million in 2000 to 366 million in 2030.(2) Many patients with diabetes are at increased risk for heart failure. This complicates their treatment, and has raised concern in recent years among some physicians that SU2s may impair the heart's ability to withstand stress, thus reducing patients' ability to survive heart attacks, says Veronique Roger, M.D., M.P.H., the Mayo cardiologist and epidemiologist who led the study.

The Mayo study is the first to use a broad population of community members to extract information about the impact of various diabetes treatments on patients' health after heart attack. The Mayo group evaluated the outcome of heart attack in two groups: people who had diabetes and those who did not. Group members were similar in terms of age, gender and lifestyle habits such as smoking. In the diabetes group, researchers tracked patient outcome after heart attack in patients taking three different treatment approaches to lowering blood sugar: SU2 drugs, insulin, diet.

“These data do not support the concern among some physicians of an adverse impact of SU2 on survival after a heart attack,” Dr. Roger says. “These results provide clinical guidance for physicians faced with managing a growing number of diabetic patients. Our study is also important because it underscores the potential role of community-based studies for helping provide evidence to clarify treatment strategies and improve care of patients.”

Using a specialized patient-records database maintained since 1936, researchers identified all heart attacks that occurred in Olmsted County, Minn., where Mayo Clinic is based, between 1979 and 2002. They identified 2,732 heart attack patients, with an average age of 70; 56 percent were women. Of the heart attack group, 486 (18 percent) also had diabetes mellitus. The diabetes patients were split into three groups and treated with SU2 drugs, insulin, or diet alone.

Collaboration and Support

Other Mayo research team members included: Richard Patch, M.D.; Adelaide Arruda-Olson, M.D., Ph.D.; Cynthia Leibson, Ph.D.; Adrian Vella, M.D.; Susan Weston; Jill Killian; and Robert Frye, M.D. Their studies were supported by the National Heart, Lung and Blood Institute of the National Institutes of Health, and Mayo Foundation for Medical Education and Research.

(1) Definitions of SU2 generics and brands come from http://www.diabetesmonitor.com/su.htm
(2) Global Prevalence of Diabetes Estimates for the year 2000 and projections for 2030. http://care.diabetesjournals.org/cgi/content/abstract/27/5/1047