Abstract
Background: The risk-benefit profile of antiarrhythmic drugs (AADs) affects the choice of pharmacotherapy for maintenance of sinus rhythm. Adverse events (AEs) associated with AADs may influence patient compliance and compromise the management of atrial fibrillation (AF). There are limited data on the incidence of AEs or persistence with AADs outside the clinical trial environment. Objective: This study provides treatment persistence and AE data for patients with AF receiving treatment with amiodarone or sotalol, 2 of the most widely used AADs in the United States. Methods: In this retrospective cohort study, patients satisfying the following criteria were identified from the US MarketScan claims databases: (1) age ≥18 years with a pharmacy claim for oral amiodarone or sotalol between 2004 and 2007; (2) ≥1 inpatient/outpatient medical claim with an AF diagnosis <90 days before the earliest (index) pharmacy claim; and (3) ≥12 months' continuous enrollment before and after the index pharmacy claim. Prespecified AE rates were compared between treatment cohorts during active treatment. Results: Among 77,093 AF patients with ≥1 claim for amiodarone or sotalol, 3459 met all inclusion criteria (mean age, 70.8 years; 61.6% male; mean Charlson Comorbidity Index [CCI], 1.58), of whom 2392 received amiodarone (mean age, 72.2 years; 62.5% male; mean CCI, 1.8) and 1067 received sotalol (mean age, 67.5 years; 59.7% male; mean CCI, 1.1). Persistence was higher among the sotalol cohort than the amiodarone cohort (53.2% vs 30.6% at 12 months; P < 0.001). Postindex versus preindex comparisons revealed increases in cardiovascular AE rates in both cohorts. Intercohort comparisons showed higher rates of cardiovascular AEs (594 vs 339 patients/1000 patient-years; P < 0.001) and pulmonary AEs (128 vs 61 patients/1000 patient-years; P < 0.001) during active amiodarone treatment. Conclusions: Among the population analyzed, patients with AF receiving amiodarone versus sotalol therapy had differing clinical characteristics. Patients experienced frequent AEs (particularly cardiovascular events) with amiodarone and sotalol, and many discontinued treatment during the first year.