Beta-Blockers, Digoxin, or Both Following an Incident Diagnosis of Atrial Fibrillation: A Prospective Cohort Study

Background: Atrial fibrillation is one of the most common arrhyth-mias, but the optimal drug choice for a rate control strategy remains uncertain. Methods: A retrospective cohort claims database study of patients with an incident hospital discharge diagnosis of atrial fibrillation be-tween 2011 and 2015. The exposure variables were a discharge prescription for beta-blockers, digoxin, or both. The primary outcome was a composite of total in-hospital mortality or a repeat cardiovas-cular (CV) hospitalization. Baseline confounding was controlled with propensity score inverse probability weighting using a entropy balancing algorithm and the prespecified estimand was the average treatment effect among the treated. Treatment effects for the weighted samples were calculated from a Cox proportional hazards model. Results: A total of 12,723 patients were discharged on beta-blockers alone, 406 on digoxin alone, and 1499 discharged on combined beta-blocker and digoxin therapy with a median follow-up time of 356 days. After baseline covariate adjustment, the digoxin alone (hazard ratio [HR], 1.24; 95% confidence interval [CI], 0.85-1.81) and the combined group (HR, 1.09; 95% CI, 0.90-1.31) were not associated with increased risk for the composite endpoint compared with the beta-blockerealone group. These results were robust to sensitivity analyses. Conclusions: Patients hospitalized for incident atrial fibrillation and discharged on digoxin alone or the combination of digoxin and a beta-blocker were not associated with an increase in the composite outcome of recurrent CV hospitalizations and death compared with those discharged on isolated beta-blocker therapy. However, additional studies are required to refine the precision of these estimates.