Digoxin-amiodarone Combination is Associated With Excess All-cause Mortality in Patients With Atrial Fibrillation

Combination use of digoxin and other medications might lead to worse outcomes in patients with atrial fibrillation (AF). We sought to investigate whether digoxin-amiodarone combination would lead to worse outcome than digoxin alone in patients with AF. Adult patients with AF and received digoxin treatment from random samples of 1,000,000 individuals covered by the National Health Insurance in Taiwan were included. Baseline characteristics including risk factors and medications were matched by propensity score (PS) in those with and without addition of amiodarone treatment. A total of 5,040 AF patients taking digoxin therapy was included. PS matching identified 1,473 patients receiving digoxin-amiodarone combination and 2,660 patients receiving digoxin with a median follow-up of 1,331 days. Digoxin-amiodarone combination was associated with increased all-cause mortality (adjusted hazard ratio (HR): 1.640, 95% confidence interval (CI): 1.470-1.829, P < 0.001). The risk of mortality increased regardless of duration of combination. Risk of sudden cardiac death was not increased in the combination group (HR: 1.304, 95% CI: 1.049-1.622, P = 0.017). Death due to non-arrhythmic cardiac disease, cerebrovascular disease, and other vascular disease were higher in the combination group than the digoxin group. In conclusion, in patients with AF, digoxin-amiodarone combination therapy is associated with excess mortality than digoxin alone.