Impact of defibrillators on mortality in patients with quadruple guideline-directed medical therapy: a propensity score-matched study

Abstract Background: In the contemporary management of heart failure with reduced ejection fraction (HFrEF), the recommended quadruple guideline-directed medical therapy (GDMT) consists of angiotensin receptor-neprilysin inhibitor (ARNI), evidence-based beta-blockers (BB), mineralocorticoid receptor antagonists(MRA), and sodium-glucose cotransporter-2 inhibitors (SGLT-2i). This study explored the impact of adding implantable cardioverter-defibrillator (ICD) therapy to this comprehensive regimen in HFrEF patients. Methods: Utilizing deidentified data from the National Electronic Database of the Turkish Ministry of Health, we conducted a nationwide retrospective cohort study on 5450 HFrEF patients receiving quadruple GDMT, including ARNI. Among them, 709 patients underwent additional ICD or cardiac resynchronization therapy defibrillator (CRT-D) implantation. Propensity score matching ensured balanced baseline characteristics between groups. Results: In the matched cohort, all-cause mortality occurred in 108 out of 619 patients (17.4%) in the GDMT group and 101 out of 619 patients (16.3%) in the ICD group, with a hazard ratio (HR) of 0.74 and a 95% confidence interval (CI) ranging from 0.57 to 0.98. Subgroup analyses consistently demonstrated benefits, particularly among individuals aged 61 years and older, those with sinus rhythm, individuals not using amiodarone, and those with an estimated glomerular filtration rate lower than 61.9. Conclusion: This study, which marked a significant milestone, suggested a complementary benefit of ICDsin reducing all-cause mortality among HFrEF patients adhering to contemporary quadruple GDMT.