Renal dysfunction is a time-varying risk predictor of sudden cardiac death in heart failure

Aims: Sudden cardiac death (SCD) is a common mode of death in patients with congestive heart failure (CHF). Implantable cardioverter defibrillator (ICD) implantation is established treatment for SCD prevention, but current eligibility criteria based on left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) functional class may be due for reconsideration given the increasing effectiveness of pharmacological therapy. We sought to reconsider the risk stratification of SCD in patients with symptomatic CHF. Methods: In total, 1,676 consecutive patients (74 ± 13 years old; 56% male) with NYHA class II or III CHF between 2008 and 2015 were enrolled for this prospective study. The endpoint was SCD. Results: During a median (interquartile range) follow-up period of 25 (4–70) months, 198 (11.8%) patients suffered SCD. Of those events, 23% occurred within 3 months of discharge. In the adjusted analyses, estimated glomerular filtration rate (eGFR) < 30 ml/min/1.73 m² [hazard ratio (HR) 1.73, 95% confidence interval (CI) 1.11–2.70, P = 0.01] and LVEF ≤ 35% (HR 2.31, 95% CI 1.47–3.66, P < 0.01) were independent risk predictors of SCD. Addition of eGFR to LVEF significantly improved prediction of SCD in the C-index (P = 0.04), and in two metrics, net reclassification improvement (P = 0.01) and integrated discrimination improvement (P = 0.03). The predictive power of eGFR declined time-dependently over 2 years. Conclusions: The addition of eGFR to current eligibility criteria may be useful for risk assessment of SCD, although its predictive power wanes over time. Roughly a quarter of the SCD occurred within 3 months after discharge in patients with CHF.