Abstract Number: PB2462
Meeting: ISTH 2020 Congress
Background: Data on oral anticoagulants (OAC) use among Venous Thromboembolism (VTE) patients in Norway is limited.
Aims: Describe demographic and clinical characteristics, trends and treatment patterns of OACs in VTE patients in Norway between 2013 and 2017.
Methods: Cohort study using prospectively collected data from the national registries in Norway between 2013 and 2017. Patients were included if they had a VTE diagnosis followed by an OAC dispensation within 30 days in this time-frame. Patients were excluded if they had presence of atrial fibrillation or a prior OAC. Kaplan Meier methods were used to assess the duration of treatment. The study was approved by the Regional Ethics Committee (2017/1328-9).
Results: 3,557 warfarin, 3,088 apixaban and 5,828 rivaroxaban patients were identified. Counts for dabigatran and edoxaban were low and are not described further. Warfarin patients were younger than apixaban (median [IQR]: 64  vs. 66  years; p=0.0045), but older than rivaroxaban (61 ; p< 0.0001). Gender distributions were similar across all groups (%female 48.5 (warfarin), 46.4 (apixaban), 43.6 (rivaroxaban)). The most prevalent comorbidity in all groups was hypertension (44%). From 2013 to 2017, of total OAC use, apixaban increased 54.5%, rivaroxaban 5.7%, warfarin declined 60.2% (Figure 1). A higher proportion of apixaban patients were persistent after 12 months of follow-up compared with warfarin, (mostly apparent after 6 months; log-rank: p< 0.0001); no difference was observed between rivaroxaban and warfarin patients (p=0.36). More than three quarters of patients, irrespective of OAC, were persistent at 3 months. At 12 months, 30.8% of patients were still persistent on apixaban, followed by 21.9% on warfarin and 19.2% on rivaroxaban (Table 1).
Conclusions: Between 2013 and 2017, apixaban and rivaroxaban use in VTE patients increased in Norway, warfarin use declined. A higher proportion of apixaban patients were persistent on treatment over time followed by warfarin and rivaroxaban.
|Kaplan-Meier estimates:||Warfarin N=3,557||Apixaban N=3,088||Rivaroxaban N=5,828|
|Length of Time on Index Therapy, months:||Median (IQR)||6.3 (3.4-10.6)||6.4 (3.7-15.9)||6.0 (3.9-9.2)|
|Patients Persistent on Treatment at Certain Timepoints, months:|
|0-3||% (95%CI)||79.7 (78.3-81.0)||83.7 (82.3-85.0)||87.4 (86.5-88.2)|
|0-6||% (95%CI)||53.1 (51.4-54.7)||53.9 (51.9-55.8)||49.7 (48.4-51.1)|
|0-9||% (95%CI)||30.3 (28.8-31.8)||36.5 (34.5-38.4)||25.4 (24.3-26.6)|
|0-12||% (95%CI)||21.9 (20.6-23.4)||30.8 (28.8-32.8)||19.2 (18.2-20.3)|
[Table 1. Median Length of Time on Therapy and Percentage of Patients Persistent on Index Therapy at Certain Timepoints (Kaplan Meier estimates)]
To cite this abstract in AMA style:Ghanima W, Halvorsen S, Brodin E, Graham S, Schultze A, Donaldson R, Carroll R, Ulvestad M, Lambrelli D. Oral Anticoagulation Therapy for Venous Thromboembolism in Norway: Patient Characteristics, Treatment Trends and Patterns [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/oral-anticoagulation-therapy-for-venous-thromboembolism-in-norway-patient-characteristics-treatment-trends-and-patterns/. Accessed September 24, 2023.
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