A model for cost effectiveness analysis of using genetic information of oral anticoagulation patients

Oral anticoagulation therapy, largely performed by warfarin-based drugs, is commonly used for patients with a high risk of blood clotting which can lead to stroke or thrombosis. The state of the patient, with respect to anticoagulation, is captured by the index INR, which is to be kept within a therapeutic range. The patient´s response is marked by high inter-individual and intertemporal variability, which can lead to serious adverse events. The food and drug administration´s adverse event reporting system indicated that warfarin is among the 10 top drugs for the adverse events reported during the 1990 and 2000 decades. Moreover in the last years genetic testing has been argued as a base to personalize dosing. For these reasons there is no widely agreed conclusion as to whether the net economic results, i.e. keeping the cost of testing into account, of the therapeutic improvement allowed by genetic testing are positive. In this paper the authors develop a model based on a decision tree to assess the cost-effectiveness of genotype based warfarin dosing. Clinical/therapeutical data inputs for the model have been derived from a database of nearly 4000 patients; among them 350 patients have been so far genotyped. Several scenarios have been simulated about the prevalence of major bleeding and their reduction rates that, following the literature, can be due to genotyped dosing.