Age-stratified comparison of prognosis in cardiac resynchronization therapy with or without prophylactic defibrillator for non-ischemic cardiomyopathy - a nationwide cohort study.

Abstract

Prior studies have suggested that the benefit from primary preventive defibrillator treatment for patients with non-ischemic cardiomyopathy primarily, treated with cardiac resynchronization therapy, may be age-dependent. We aimed to compare age-stratified mortality rates and mode of death in patients with non-ischemic cardiomyopathy who are treated with either primary preventive Cardiac Resynchronization Therapy-defibrillator (CRT-D) or CRT-pacemaker (CRT-P). All patients with non-ischemic cardiomyopathy and CRT-P or primary preventive CRT-D who were implanted in Sweden during the period 2005-2020 were included. Propensity scoring was used to create a matched cohort. Primary outcome was all-cause mortality within five years. 4027 patients were included, 2334 with CRT-P and 1693 with CRT-D. Crude 5-year mortality was 635 (27%) vs. 246 (15%), p < 0.001. In Cox regression analysis, adjusted for clinically relevant covariables, CRT-D was independently associated with higher five-year survival (0.72 [0.61-0.85], p < 0.001). Cardiovascular mortality was similar between groups (62% vs. 64%, p = 0.64), but death from heart failure was more common in the CRT-D group (46% vs. 36%, p = 0.007). In the matched cohort (n = 2414), five-year mortality was 21% (24% versus 16%, p < 0.001). In age-stratified analyses, CRT-P was associated with higher mortality in age-groups <60 years and 70-79 years, but there was no difference in age groups 60-69 years or 80-89 years. In this nationwide registry-based study, patients with CRT-D have better five-year survival compared to patients with CRT-P. The interaction between age and mortality reduction not consistent, but patients with CRT-D aged <60 years had the largest absolute mortality reduction.