Amiodarone vs Dronedarone Treatments in Patients With Atrial Fibrillation

Patients hospitalized for atrial fibrillation (AF) and subsequently discharged on dronedarone experience a small increase in repeat cardiovascular (CV) hospitalization and mortality across a median 1-year follow-up, according to study findings published in the Journal of the Canadian Cardiovascular Society.

Investigators aimed to compare the real-world effectiveness of amiodarone vs dronedarone among patients hospitalized for AF. A discharge prescription for amiodarone or dronedarone represented exposure variables. The primary endpoint was the average treatment effect for the composite of repeat CV hospitalization and mortality during a 12-month follow-up.

They conducted a retrospective cohort study using data from the Truven Health Market Scan Commercial Claims and Encounters and Medicare Supplemental databases that included patients with a new diagnosis of AF with a discharge date from 2011 through 2015. They included 1735 patients discharged on amiodarone and 338 patients discharged on dronedarone and a median follow-up of 357 days (or receiving prescriptions within 2 days of discharge) from 52,164 atrial fibrillation hospitalizations. No included patients received additional anti-arrhythmic drugs upon discharge.

The investigators noted the amiodarone cohort was older (67 [SD, 11.3] years vs 63.9 [SD, 11.4] years) and had more comorbidities.

The investigators observed a statistically significant risk difference (RD) of 12.7% CV rehospitalizations among the dronedarone cohort and 8.4% CV rehospitalizations among the amiodarone cohort (RD, 4.3%; 95% CI, 0.4%-8.3%; P =.02). They found a non-statistically significant risk difference of 1.2% deaths among the dronedarone cohort and 1.8% mortality among the amiodarone cohort (RD, -0.6%; 95% CI, -2.1 to 0.9%; P =.6).

After investigators adjusted for baseline covariates, the dronedarone hazard ratio for the composite primary endpoint was 1.47 (95% CI, 1.01-2.12) for the average treatment effect which also revealed no statistical significance. The average treatment effect was the prespecified primary analysis for the study.

The investigators noted the primary diagnosis for recurrent hospitalization was AF with the amiodarone cohort (5.13%) and dronedarone cohort (11.54%). They noticed no statistically significant differences between the medications for other CV hospitalizations.

Significant study limitations include the sample size being underpowered to examine mortality as a separate outcome and potential confounders that are unaccounted for. There is also a large number of patients not filling a prescription upon discharge.

“…compared to those discharged on amiodarone, patients receiving a dronedarone discharge prescription had an increase in the composite endpoint of recurrent CV hospitalizations and death over a median 1-year follow-up,” the study authors wrote.

Disclosure: One study author declared affiliations with industry. Please refer to the original article for a full list of disclosures.