Outcomes of Early Rhythm Control Therapy in Patients with Atrial Fibrillation and a High Comorbidity Burden in Large Real-World Cohorts

Background: A recent subanalysis of the EAST-AFNET 4 (Early Treatment of Atrial Fibrillation for Stroke Prevention Trial) suggests a stronger benefit of early rhythm control (ERC) in patients with atrial fibrillation and a high comorbidity burden when compared to patients with a lower comorbidity burden. Methods: We identified 109 739 patients with newly diagnosed atrial fibrillation in a large United States deidentified administrative claims database (OptumLabs) and 11 625 patients in the population-based UKB (UK Biobank). ERC was defined as atrial fibrillation ablation or antiarrhythmic drug therapy within the first year after atrial fibrillation diagnosis. Patients were classified as (1) ERC and high comorbidity burden (CHA₂DS₂-VASc score ≥4); (2) ERC and lower comorbidity burden (CHA₂DS₂-VASc score 2-3); (3) no ERC and high comorbidity burden; and (4) no ERC and lower comorbidity burden. Patients without an elevated comorbidity burden (CHA₂DS₂-VASc score 0-1) were excluded. Propensity score overlap weighting and cox proportional hazards regression were used to balance patients and compare groups for the primary composite outcome of all-cause mortality, stroke, or hospitalization with the diagnoses heart failure or myocardial infarction as well as for a primary composite safety outcome of death, stroke, and serious adverse events related to ERC. Results: In both cohorts, ERC was associated with a reduced risk for the primary composite outcome in patients with a high comorbidity burden (OptumLabs: hazard ratio, 0.83 [95% CI 0.72-0.95]; P=0.006; UKB: hazard ratio, 0.77 [95% CI, 0.63-0.94]; P=0.009). In patients with a lower comorbidity burden, the difference in outcomes was not significant (OptumLabs: hazard ratio, 0.92 [95% CI, 0.54-1.57]; P=0.767; UKB: hazard ratio, 0.94 [95% CI, 0.83-1.06]; P=0.310). The comorbidity burden interacted with ERC in the UKB (interaction- P=0.027) but not in OptumLabs (interaction-P=0.720). ERC was not associated with an increased risk for the primary safety outcome. Conclusions: ERC is safe and may be more favorable in a population-based sample of patients with high a comorbidity burden (CHA₂DS₂-VASc score ≥4).