Comparisons of hospitalization rates among younger atrial fibrillation patients receiving different antiarrhythmic drugs

Background - Antiarrhythmic drugs (AADs) are used to reduce the frequency, severity, and duration of atrial fibrillation (AF) events, which should reduce hospitalizations; however, little is known about the associations between different AADs and hospitalization - particularly among younger AF patients without structural heart disease. Methods and Results - Using MarketScan® claims data, we identified AF patients without coronary artery disease or heart failure who received their first AAD prescription (amiodarone, sotalol, dronedarone, or Class Ic) within 14 days post-first AF encounter. The primary outcome was time from first AAD prescription to AF hospitalization, and secondary outcomes included time to cardiovascular and all-cause hospitalizations. We used inverse probability-weighted estimators to adjust for differences in treatment allocation in the Cox proportional hazards model for each outcome. Among 8562 AF patients with a median age of 56 years (interquartile range 49, 61), risk of AF hospitalization was greater with dronedarone than Class Ic (hazard ratio [HR] 1.59; 95% confidence interval 1.13-2.24), amiodarone (HR 2.63; 1.77-3.89), and sotalol (HR 1.72; 1.17-2.54), but lower with amiodarone versus Class Ic (HR 0.68; 0.57-0.80) and sotalol (HR 0.63; 0.53-0.75). Risk of cardiovascular hospitalization was lower with amiodarone than Class Ic (HR 0.80; 0.70-0.92), but not non-AF cardiovascular hospitalization (HR 1.26; 1.01-1.57). There was no difference in all-cause hospitalization between amiodarone, Class Ic, and sotalol. Conclusions - Differences in hospitalization rates were found between AADs in younger AF patients without structural heart disease. Amiodarone had the lowest risk of AF hospitalization and dronedarone had the greatest risk. Additional research is needed to better understand associations between AADs and hospitalization risk.