Aims: An implantable cardioverter-defibrillator (ICD) is recommended for reducing the risk of sudden cardiac death (SCD) in myocardial infarction (MI) patients with a left ventricular ejection fraction (LVEF) ≤ 30%, as well as patients with a LVEF ≤ 35% and heart failure symptoms. Diabetes and/or impaired kidney function may confer additional SCD risk. We assessed the association between these two risk factors with SCD and non-SCD among MI survivors taking account of age and LVEF.
Methods and results: A total of 17 773 patients from the High-Risk MI Database were evaluated. Overall, diabetes and estimated glomerular filtration rate < 60 mL/min/1.73 m2 , individually and together, conferred a higher risk of SCD [adjusted competing risk: hazard ratio (HR) 1.23, 1.23, and 1.32, respectively; all P < 0.03] and non-SCD (HR 1.34, 1.52, and 2.13, respectively; all P < 0.0001). Annual SCD rates in patients with LVEF > 35% and with diabetes, impaired kidney function, or both (2.0%, 2.5% and 2.7%, respectively) were comparable to rates observed in patients with LVEF 30-35% but no such risk factors (1.7%). However, these patients had also similarly higher non-SCD rates, such that the ratio of SCD to non-SCD was not increased. Importantly, this ratio was mostly dependent on age, with higher overall ratios in youngest subgroups (0.89 in patients < 55 years vs. 0.38 in patients ≥ 75 years), regardless of risk factors.
Conclusion: Although MI survivors with LVEF > 35% with diabetes, impaired kidney function, or both are at increased risk of SCD, the risk of non-SCD risk is even higher, suggesting an extension of the current indication for an ICD to them is unlikely to be worthwhile. MI survivors with low LVEF and aged < 55 years are likely to have the greatest potential benefit from ICD implantation.
Keywords: Diabetes; Impaired kidney function; Left ventricular dysfunction; Myocardial infarction; Sudden cardiac death.
© 2019 The Authors. European Journal of Heart Failure © 2019 European Society of Cardiology.