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

OBJECTIVES: This study sought to determine the absolute and relative associations of diabetes mellitus (DM) and hemoglobin A1c (HbA1c) 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 HbA1c 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 HbA1c 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 HbA1c 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 HbA1c. In analyses limited to patients with DM, HbA1c 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 HbA1c are at much higher absolute risk of dying from non-SAD than SAD. Clinical risk markers, and not HbA1c, were associated with SAD risk in patients with DM. (PRE-DETERMINE: Biologic Markers and MRI SCD Cohort Study; NCT01114269).