OBJECTIVES: The ATHENA trial demonstrated that in patients with atrial fibrillation (AF) and/or atrial flutter (AFL), dronedarone decreased the risk of CV hospitalizations or death from any cause by 24% (P<0.001). In this retrospective cohort study, we evaluated hospitalizations/mortality in three subgroups of real world US insured AF/AFL patients without heart failure (HF): 1) patients aged ≥65 years (with or without CV risk factors); 2) ATHENA-like patients (≥70 years and ≥1 CV risk factor); and 3) ATHENA-like patients ≥75 years. METHODS: Data for patients with evidence of non-transient AF and/or AFL in 2005 were drawn from the US MarketScan® databases from Thomson Reuters. Patients also had to have ≥12 months’ continuous enrollment pre- and post-AF/AFL index diagnosis (except for inpatient death). RESULTS: In the AF/AFL ≥65 years, ATHENA ≥70 years, and ATHENA ≥75 years groups, 55,774 (52.2% men), 32,262 (46.2% men) and 24,587 (43.6% men) patients, respectively, were identified. Mean follow up was 24 months in all 3 groups. Across the 3 groups, more than half of patients had ≥1 hospital admission (51.9%, 52.7%, and 54.5%, respectively) and almost 30% a hospitalization with a primary CV diagnosis (27.2%, 28.2%, and 28.7%, respectively). Inpatient deaths were reported in 1592 (2.9%) AF/AFL ≥65 years, 919 (2.8%) ATHENA ≥70 years, and 798 (3.2%) ATHENA ≥75 years patients. Deaths during hospitalizations for CV causes were reported in 516 (0.9%), 327 (1.0%), and 273 (1.1%) patients, respectively. CONCLUSIONS: There was a similar rate of hospitalization and mortality between the two ATHENA-like groups and the AF/AFL ≥65 year group. The three patient groups studied were frequently hospitalized for all causes and CV events. Dronedarone may therefore be of benefit to a large number of ATHENA-like AF/AFL patients in a real-world setting. Further studies should evaluate dronedarone in a broader range of AF/AFL patients aged ≥65 years.