Assessing the direct costs of treating nonvalvular atrial fibrillation in the United States.

Objective: To determine the health-care resource use and costs attributable to treating atrial fibrillation (AF) in the United States.

Methods: Retrospective analyses of three federally funded US databases (2001 data): 1) hospital inpatient stays (the Healthcare Cost and Utilization Project [HCUP]); 2) physician office visits (the National Ambulatory Medical Care Survey [NAMCS]); and 3) emergency department (ED) and hospital outpatient department visits (OPD) (the National Hospital Ambulatory Medical Care Survey [NHAMCS]). Identification of AF medical encounters was based on occurrence of AF-specific International Classification of Diseases (9th Edition)--Clinical Modification (ICD-9-CM) diagnosis code 427.31 (principal discharge diagnosis for inpatient setting; any diagnosis field for other settings). For the 10 most common principal discharge diagnoses in the inpatient setting, case-control comparison analyses were performed to estimate annual incremental costs of AF as a comorbid discharge diagnosis for hospital stays. Regression models were used to assess the impact of AF on hospitalization costs. Costs were estimated in year 2005 US dollars.

Results: Approximately 350,000 hospitalizations, 5.0 million office visits, 276,000 ED visits, and 234,000 OPD were attributable to AF annually within the United States. Total annual costs for treatment of AF were estimated at $6.65 billion, including $2.93 billion (44%) for hospitalizations with a principal discharge diagnosis of AF, $1.95 billion (29%) for the incremental inpatient cost of AF as a comorbid diagnosis, $1.53 billion (23%) for outpatient treatment of AF, and $235 million (4%) for prescription drugs. In all regressions, AF was a significant contributor to hospital cost.

Conclusions: Treatment of AF represents a significant health-care burden with the costs of treating AF in the inpatient setting outweighing the costs of treating AF in the office, emergency room or hospital outpatient settings. Further research is needed to fully capture the costs of treating AF.