Cost Implications of Formulary Decisions on Oral Anticoagulants in Nonvalvular Atrial Fibrillation

BACKGROUND: Nonvalvular atrial fibrillation (AF) is a major public health issue. The major complication of AF is an increased risk of stroke. Warfarin, long used for stroke prophylaxis in AF patients, has a narrow therapeutic window and numerous food and drug interactions necessitating regular laboratory monitoring. New oral anticoagulants (e.g., dabigatran, rivaroxaban, apixaban) may meet the need for predictable anticoagulation with fixed, unmonitored dosing. OBJECTIVE: To review costs of monitoring, bleeding, and stroke in AF patients to analyze costs of anticoagulants for stroke prophylaxis in AF patients. METHODS: A literature search on the costs of treating AF used PubMed/MEDLINE databases (to April 2012) focusing on studies in the United States. Key words or MeSH terms were used, such as "observational studies," "oral anticoagulants," "warfarin," "cost of bleeding," "cost of stroke," and "cost of INR monitoring." RESULTS: The literature focused mainly on short-term, in-hospital expenditures and less on long-term care costs. Annual overall costs per patient for treating AF in the United States ranged from $18,454 to $38,270. Annual incremental costs of treating AF ranged from $8,705 to $16,311. Annual inpatient costs ranged from $7,841 to $22,582 per patient. Annual costs of anticoagulation monitoring ranged from $291 to $943 per patient. Intracranial hemorrhage and major gastrointestinal bleeding with oral anticoagulants were uncommon but expensive: 1-year costs ranged from $7,584 to $193,804. Annual direct costs of stroke in AF patients ranged from $23,143 to $37,620 (incremental cost of $7,824 to $8,232 vs. AF patients without stroke). CONCLUSIONS: AF-associated direct costs are high and can be broken into costs of warfarin monitoring and direct costs of managing consequences of anticoagulant therapy-stroke and bleeding.