Given that 4 million individuals in the United States have atrial fibrillation, understanding the epidemiology of this disease is crucial. We sought to identify and characterize the impact of age on national atrial fibrillation hospitalization patterns.

The study sample was drawn from the 2009-2010 Nationwide Inpatient Sample. Patients hospitalized with a principal International Classification of Diseases, 9th Revision discharge diagnosis of atrial fibrillation were included. Patients were categorized as “older” (≥65 years) or “younger” (<65 years) for the purposes of analysis. The outcomes measured included hospitalization rate, length of stay, in-hospital mortality, and discharge status.

We identified 192,846 atrial fibrillation hospitalizations. There was significant geographic variation in hospitalizations for both younger and older age groups. States with high hospitalizations differed from those states known to have high stroke mortality. Younger patients (33% of the sample) were more likely to be obese (21% vs 8%, P < .001) and to use alcohol (8% vs 2%, P < .001). Older patients were more likely to have kidney disease (14% vs 7%, P < .001). Both age groups had high rates of hypertension and diabetes. Older patients had higher in-hospital mortality and were more likely to be discharged to a nursing or intermediate care facility.

Younger patients account for a substantial minority of atrial fibrillation hospitalizations in contemporary practice. Younger patients are healthier, with a different distribution of risk factors, than older patients who have higher associated morbidity and mortality.