Diabetes increases risk of death for patients with acute coronary syndromes

Aug 16 2007

Individuals with diabetes and acute coronary syndromes (ACS) such as a heart attack or unstable angina have an increased risk of death at 30 days and one year after ACS, compared with ACS patients without diabetes, according to a study in the August 15 issue of JAMA.

“The presence of elevated blood glucose levels, diabetes mellitus, or both contributes to more than 3 million cardiovascular deaths worldwide each year. With the increase in obesity, insulin resistance, and the metabolic syndrome, the worldwide prevalence of diabetes is expected to double by the year 2030,” the authors write. They add that more than 1.5 million adults in the U.S. were newly diagnosed with diabetes in 2005, and nearly 65 percent of individuals with diabetes die from cardiovascular disease in the U.S., establishing it as the leading cause of death among this growing segment of the population. The effect of diabetes on the risk of death following ACS is uncertain.

Sean M. Donahoe, M.D., of Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues evaluated the independent effect of diabetes on risk of death following ACS at 30 days and 1 year using a large clinical trial database that included ACS. The study consisted of an analysis of patients with diabetes enrolled in randomized controlled trials that evaluated ACS therapies. Patients with ACS in 11 independent Thrombolysis in Myocardial Infarction (TIMI) Study Group clinical trials from 1997 to 2006 were pooled, including 62,036 patients (46,577 with ST-segment elevation myocardial infarction [STEMI; a certain pattern on an electrocardiogram following a heart attack] and 15,459 with unstable angina/non–STEMI [UA/NSTEMI]), of whom 10,613 (17.1 percent) had diabetes.

The researchers found that the rate of death was significantly higher among patients with diabetes than among patients without diabetes at 30 days following either UA/NSTEMI (2.1 percent vs. 1.1 percent) or STEMI (8.5 percent vs. 5.4 percent). After adjusting for baseline characteristics and features and management of the ACS event, diabetes was independently associated with a nearly 80 percent increased risk of death at 30-days after UA/NSTEMI, and 40 percent increased risk of death at 30-days after STEMI.

At 1 year, diabetes remained a significant independent factor associated with all-cause death for patients presenting with UA/NSTEMI (65 percent increased risk of death) or STEMI (22 percent increased risk of death). By 1 year following ACS, patients with diabetes presenting with UA/NSTEMI had a risk of death that approached patients without diabetes presenting with STEMI (7.2 percent vs. 8.1 percent).

“Despite modern therapies for ACS, diabetes conferred a significant independent excess mortality risk at 30 days and 1 year following ACS. Current strategies are insufficient to ameliorate the adverse impact of diabetes. Given the increasing burden of cardiovascular disease attributable to diabetes worldwide, our study highlights the need for a major research effort to identify aggressive new strategies to manage unstable ischemic heart disease among this high-risk population,” the authors conclude.