Previous studies on digoxin use in patients with atrial fibrillation (AF) and the risk of all-cause mortality found conflicting results. We conducted a population-based, retrospective, cohort study of patients aged ≥65 years admitted to a hospital with a primary or secondary diagnosis of AF, in Quebec province, Canada, from 1998 to 2012. The AF cohort was grouped into patients with and without heart failure (HF) and into digoxin and no-digoxin users according to the first prescription filled for digoxin within 30 days after AF hospital discharge. We derived propensity score-matched digoxin and no-digoxin treatment groups for the groups of patients with and without HF, respectively, and conducted multivariable Cox proportional hazards regression analyses to determine association between digoxin use and all-cause mortality. The AF propensity score-matched cohorts of patients with and without HF were well balanced on baseline characteristics. In the propensity score-matched HF group, digoxin use was associated with a 14% greater risk of all-cause mortality (adjusted hazard ratio 1.14, 95% confidence interval 1.10 to 1.17). In the propensity score-matched no-HF group, digoxin use was associated with a 17% greater risk of all-cause mortality (adjusted hazard ratio 1.17, 95% confidence interval 1.14 to 1.19). In conclusion, our retrospective analyses found that digoxin use was associated with a greater risk for all-cause mortality in patients aged ≥65 years with AF regardless of concomitant HF. Large, multicenter, randomized controlled trials or prospective cohort studies are required to clarify this issue.
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