A geospatial model to determine the spatial cost-efficiency of anticoagulation drug therapy: Patients' perspective

Most atrial fibrillation (AF) patients need anticoagulation management to reduce the risk of thromboembolic events and stroke. Currently, two major drug therapies are available: warfarin and direct oral anticoagulant (DOAC). This study examined the spatial costs of these therapies and derived the least-cost market areas for both therapies in the study area. The concepts of spatial costs and the principles of forming market areas were used as theoretical starting points, and the patients' travel, time-loss, and medication cost parameters combined with geographical information systems methods were incorporated into the geospatial model. Results showed that for AF patients who live near the international normalized ratio (INR) monitoring sample collection point and have less than 15 annual INR monitoring visits, warfarin therapy resulted in the lowest cost regardless of patient's travel mode and their assumed working or retirement status. If the AF patient needs more frequent INR monitoring visits or lives farther from the nearest sample collection point, DOAC would be the least costly option. The modelled results reveal the variety and importance of patients' cost of time loss and travel costs when a physician selects the appropriate anticoagulation therapy.