Lisette van Dam

Cost-effectiveness of MRI for diagnosing recurrent ipsilateral DVT 3 39 and clinically relevant non-major (CRNM) bleeding were defined according to the International Society on Thrombosis and Haemostasis ( ISTH ) criteria. 18,19 Costs One-year health care costs are reported in euros at price level of 2019 and included diagnostic, anticoagulant medication, management and bleeding complication costs ( Table 1 ). The diagnostic costs included initial admission costs at the emergency department (ED) and costs for basic laboratory measurements for all patients. Depending on the diagnostic scenario, additional costs for the diagnostic tests (D-dimer, CUS and/or MRDTI) were included. Anticoagulant medication costs for a 1-year period were calculated including the price of the medication itself (including value-added tax) and an additional €6 delivery costs of the medication per regular delivery. 20 Data from IQVIA, a global health care data source company, were used to estimate the proportions of the different types of anticoagulants, including DOACs, vitamin K antagonists (VKAs) and low-molecular weight heparins (LMWHs). For the estimation of the costs of LMWH, the price of Nadroparin was used, since it is the most prescribed LMWH in the Netherlands. 21 Since data of the average body weight in the Theia study population were not available, we used the mean body weight from a recent Dutch study, in which a CDR was evaluated in patients with suspected acute PE. 22 For the estimation of the management costs, costs for hospital admission, outpatient visits and compression stockings for patients diagnosed with recurrent DVT were calculated. Data on hospital admission rate and duration were not available for the Theia study population. Therefore, hospital admission costs were estimated assuming that 14% of patients diagnosed with recurrent DVT would be hospitalized, for a mean duration of 7.2 days, based on available literature. 23,24 The outpatient visit costs included 2 routine visits which was in accordance with local hospital protocols. We estimated that all patients diagnosed with recurrent DVT (at baseline or during follow-up period) would be treated with (at least) 1 pair of class II compression stockings. Finally, costs caused by bleeding complications were calculated by multiplying the costs per complication with the estimated risk for bleeding in VKA and DOAC treatment and the estimated number of VKA and DOAC users ( Table 1 ). The risk for bleeding in VKA versus DOAC treatment was obtained from previous publications