Hyperglycaemia, ejection fraction and the risk of heart failure or cardiovascular death in patients with type 2 diabetes and a recent acute coronary syndrome

Chronic hyperglycaemia, assessed by elevated glycated haemoglobin (A1C), is a known risk factor for heart failure (HF) and cardiovascular (CV) death among subjects with diabetes. Whether this risk varies with left ventricular ejection fraction (LVEF) is unknown. This study evaluated whether A1C influences a composite outcome of either HF hospitalization or CV death differently along the spectrum of LVEF.

Methods and results
We assessed the relationships of baseline A1C and LVEF with a composite outcome of either CV death or HF hospitalization in the 4091 patients with type 2 diabetes and a recent acute coronary syndrome enrolled in the ELIXA trial who had available LVEF. We assessed for interaction between A1C and LVEF as continuous variables with respect to this outcome. During a median follow-up of 25.7 months, 343 patients (8.4%) had HF hospitalization or died of CV causes. In a multivariable model, A1C and LVEF were each associated with an increased risk of HF hospitalization or CV death [adjusted hazard ratio (HR) 1.11, 95% confidence interval (CI) 1.01–1.21 per 1% higher A1C, and adjusted HR 1.39, 95% CI 1.27–1.51 per 10% lower in LVEF]. Both A1C and LVEF were independently and incrementally associated with risk without evidence of interaction (P for interaction = 0.31). Patients with A1C ≥ 8% and LVEF <40% were at threefold higher risk than those with A1C < 7% and LVEF ≥50% (adjusted HR 3.18, 95% CI 2.03–4.98, P < 0.001).

Conclusion
In a contemporary cohort of patients with type 2 diabetes and acute coronary syndrome, baseline chronic hyperglycaemia was associated with an increased risk of HF hospitalization or CV death independently of LVEF.