Genotype-Guided Warfarin Dosing in Arial Fibrillation

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Genotype-Guided Warfarin Dosing in Arial Fibrillation

Patrick AR, Avorn J, Choudhry NK. Cost-Effectiveness of Genotype-Guided Warfarin Dosing for Patients With Atrial Fibrillation. Circ Cardiovasc Qual Outcomes published 21 July 2009,


Circulation: Cardiovascular Quality and Outcomes. 2009
Published online before print July 21, 2009, doi: 10.1161/CIRCOUTCOMES.108.808592

Original Article
Cost-Effectiveness of Genotype-Guided Warfarin Dosing for Patients With Atrial Fibrillation
Amanda R. Patrick, MS; Jerry Avorn, MD and Niteesh K. Choudhry, MD, PhD
From the Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Mass.
Correspondence to Amanda Patrick, Brigham and Women's Hospital, Division of Pharmacoepidemiology, 1620 Tremont St, Suite 3030, Boston, MA 02120. E-mail

Background: CYP2C9 and VKORC1 genotyping has been advocated as a means of improving the accuracy of warfarin dosing. However, the effectiveness of genotyping in improving anticoagulation control and reducing major bleeding has not yet been compellingly demonstrated. Genotyping currently costs $400 to $550.
Methods and Results: We constructed a Markov model to evaluate whether and under what circumstances genetically-guided warfarin dosing could be cost-effective for newly diagnosed atrial fibrillation patients. Estimates of clinical event rates, treatment and adverse event costs, and utilities for health states were derived from the published literature. The cost-effectiveness of genetically-guided dosing was highly dependent on the assumed effectiveness of genotyping in increasing the amount of time patients spend appropriately anticoagulated. If genotyping increases the time spent in the target international normalized ratio range by Conclusions: Our results suggest that genotyping before warfarin initiation will be cost-effective for patients with atrial fibrillation only if it reduces out-of-range international normalized ratio values by more than 5 to 9 percentage points compared with usual care. Given the current uncertainty surrounding genotyping efficacy, caution should be taken in advocating the widespread adoption of this strategy.

Key Words: anticoagulants • genetics • cost-benefit analysis • arrhythmias, cardiac

Copyright © 2009 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited.