Diabetes and Risk of Sudden Death in Coronary Artery Disease Patients Without Severe Systolic Dysfunction

Abstract

Objectives: This study sought to determine the absolute and relative associations of diabetes mellitus (DM) and hemoglobin A_1c (HbA_1c) with sudden and/or arrhythmic death (SAD) versus other modes of death in patients with coronary artery disease (CAD) who do not qualify for implantable cardioverter-defibrillators.

Background: Patients with CAD and DM are at elevated risk for SAD; however, it is unclear whether these patients would benefit from implantable cardioverter-defibrillators given competing causes of death and/or whether HbA_1c might augment SAD risk stratification.

Methods: In the PRE-DETERMINE study of 5,764 patients with CAD with left ventricular ejection fraction (LVEF) of >30% to 35%, competing risk analyses were used to compare the absolute and relative risks of SAD versus non-SAD by DM status and HbA_1c level and to identify risk factors for SAD among 1,782 patients with DM.

Results: Over a median follow-up of 6.8 years, DM and HbA_1c were significantly associated with SAD and non-SAD (P < 0.05 for all comparisons); however, the cumulative incidence of non-SAD (19.2%; 95% CI: 17.3%-21.2%) was almost 4 times higher than SAD (4.8%; 95% CI: 3.8%-5.9%) in DM patients. A similar pattern of absolute risk was observed across categories of HbA_1c. In analyses limited to patients with DM, HbA_1c was not associated with SAD, whereas low LVEF, atrial fibrillation, and electrocardiogram measurements were associated with higher SAD risk.

Conclusions: In patients with CAD and LVEF of >30% to 35%, patients with DM and/or elevated HbA_1c are at much higher absolute risk of dying from non-SAD than SAD. Clinical risk markers, and not HbA_1c, were associated with SAD risk in patients with DM. (PRE-DETERMINE: Biologic Markers and MRI SCD Cohort Study; NCT01114269).

Keywords: HbA(1c); diabetes mellitus; risk stratification; sudden cardiac death.