Survival of patients undergoing cardiac resynchronization therapy with or without defibrillator: the RESET-CRT project

AIMS: Cardiac resynchronization therapy (CRT) is an established treatment for heart failure. There is contradictory evidence whether defibrillator capability improves prognosis in patients receiving CRT. We compared the survival of patients undergoing de novo implantation of a CRT with defibrillator (CRT-D) option and CRT with pacemaker (CRT-P) in a large health claims database. METHODS AND RESULTS: Using health claims data of a major German statutory health insurance, we analysed patients with de novo CRT implantation from 2014 to 2019 without indication for defibrillator implantation for secondary prevention of sudden cardiac death. We performed age-adjusted Cox proportional hazard regression and entropy balancing to calculate weights to control for baseline imbalances. The analysis comprised 847 CRT-P and 2722 CRT-D patients. Overall, 714 deaths were recorded during a median follow-up of 2.35 years. A higher cumulative incidence of all-cause death was observed in the initial unadjusted Kaplan-Meier time-to-event analysis [hazard ratio (HR): 1.63, 95% confidence interval (CI): 1.38-1.92]. After adjustment for age, HR was 1.13 (95% CI: 0.95-1.35) and after entropy balancing 0.99 (95% CI: 0.81-1.20). No survival differences were found in different age groups. The results were robust in sensitivity analyses. CONCLUSION: In a large health claims database of CRT implantations performed in a contemporary setting, CRT-P treatment was not associated with inferior survival compared with CRT-D. Age differences accounted for the greatest part of the survival difference that was observed in the initial unadjusted analysis.