Having type 2 diabetes is an independent risk factor for sudden cardiac death after experiencing an MI, according to research published in the October issue of Heart Rhythm. But whether guidelines for implantable cardioverter-defibrillators in these patients need to be revised requires more study.
The study found that the incidence of sudden cardiac death in diabetic patients with a left ventricular ejection fraction (LVEF) greater than 35 percent was equal to that of nondiabetic patients with LVEF less than 35 percent.
In addition, a secondary analysis by M. Juhani Junttila, MD, from the University of Miami Miller School of Medicine in Miami, Fla., and colleagues found that non-sudden cardiac deaths were higher among diabetics after a heart attack compared with nondiabetics.
Between 1996 and 2005, Junttila and colleagues followed for five years a cohort of 3,276 patients enrolled into the study at the time of acute MI. At entry into the study, diabetes was present in 19.2 percent of patients.
Researchers found that sudden cardiac death occurred in 5.9 percent of the diabetic patient population compared to 1.7 percent of the nondiabetic patients. The cumulative all-cause mortality rate among the diabetic population was 21 percent compared to 8.4 percent among the nondiabetic population.
After adjustments for gender, age, hypertension, prior MI, LVEF and other factors, study analysis found type 2 diabetes to be an independent predictor of sudden cardiac death. In a subgroup analysis, researchers found that the incidence of sudden cardiac death among diabetic patients with LVEF greater than 35 percent was nearly identical to that of nondiabetic patients with LVEF less than 35 percent.
"A striking result from our study is the observance of equivalent sudden cardiac death risk between diabetic patients with ejection fractions greater than 35 percent and nondiabetic patients with ejection fractions less than 35 percent," said Junttila. "These observances may have implications for the interpretation of evidence-based criteria for ICD therapy after MI, but further studies are needed to determine whether type 2 diabetic patients who have had an MI would benefit from modifications of ICD guidelines."