Genetic testing of all patients about to start on the blood thinner warfarin is not cost-effective, say researchers.
Warfarin is a popular anticoagulant drug often given to patients with the form of abnormal heart rhythm called atrial fibrillation. In 2007, the US Food and Drug Administration changed warfarin’s labelling, suggesting that clinicians consider genetic testing before treatment in order to determine optimum dosage, as certain genes are linked to an increased sensitivity to the drug.
But a new analysis by Dr Mark Eckman and colleagues at the University of Cincinnati, USA, raises doubts over this approach. In the Annals of Internal Medicine, they report on their analysis of three clinical studies on pharmacogenetic-guided dosing and risk of major bleeds.
They found it led to better outcomes, but at a cost of over 170,000 US dollars per quality-adjusted life year gained. The team conclude that there is only a ten per cent chance that genotype-guided dosing is likely to be cost-effective. However, it might be worth the cost when used for patients at high risk of hemorrhage.
Dr Eckman said: "The hope is that more accurate dosing will translate into decreased major bleeds during the initiation phase of warfarin dosing, which is the first month or so. This could be accomplished if testing were done in-house, at lower cost and without delays."
He added that future studies must look at the long-term impact of pharmacogenetic-guided dosing on bleeding risk.
Dr Eckman concluded: "Personalised, predictive medicine offers great promise, but we need to carefully examine the benefits and understand the cost-effectiveness of such strategies before we spend a lot of money on very expensive tests."
Eckman, M. R. et al. Cost-Effectiveness of Using Pharmacogenetic Information in Warfarin Dosing for Patients With Nonvalvular Atrial Fibrillation. Annals of Internal Medicine, Vol. 150, January 20, 2009, pp. 73-83.
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