Background: Patients with venous thromboembolism (VTE) often have comorbidities requiring antiplatelet use. Thus, the effects of concomitant use of direct oral anticoagulants (DOACs) and antiplatelets in this population are of great importance. To date, post-hoc analyses of randomized trials have provided inconclusive evidence, while ‘real-world’ studies are lacking.
Aims: To assess the effectiveness and safety of concomitant use of DOACs and antiplatelets versus concomitant use of vitamin K antagonists (VKAs) and antiplatelets among VTE patients in routine clinical practice.
Methods: We conducted a multi-national cohort study using administrative databases from Germany and Québec. We assembled two population-based cohorts of patients with incident VTE initiating concomitant use of a DOAC or a VKA with antiplatelets within 15 days of the VTE. Date of cohort entry was day 15 after the incident VTE. Study period spanned from 01/2012 to the most recent date of data availability (Germany: 12/2019; Québec: 12/2015). Using an as-treated exposure definition, we compared concomitant use of DOACs and antiplatelets to concomitant use of VKAs and antiplatelets. We applied propensity score-based inverse probability of treatment weighting to balance exposure groups. Cox models estimated site-specific hazard ratios (HRs) and 95% confidence intervals (CIs) of recurrent VTE, major bleeding, and all-cause mortality. The results were meta-analyzed using random-effects models.
Results: Our cohort included 4,973 (Germany: n=1,729; Québec: n=3,244) VTE patients intiating concomitant use of a DOAC (n=2,291) or a VKA (n=2,682) with antiplatelets. Compared to concomitant VKA-antiplatelet use, concomitant DOAC-antiplatelet use was associated with a similar risk of recurrent VTE (HR, 0.96; 95% CI, 0.40-2.27), a numerically decreased risk of major bleeding (HR, 0.84; 95% CI, 0.45-1.59) and a numerically increased risk of all-cause mortality (HR, 1.27; 95% CI, 0.88-1.83).
Conclusions: Among VTE patients using antiplatelets, DOACs showed a comparable effectiveness and safety compared with VKAs. Further studies are needed to improve the precision of findings.
To cite this abstract in AMA style:Douros A, Basedow F, Cui Y, Enders D, Tagalakis V. Effectiveness and Safety of Concomitant Use of Direct Oral Anticoagulants and Antiplatelet Agents among Patients with Venous Thromboembolism: A Population-based Multinational Cohort Study [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/effectiveness-and-safety-of-concomitant-use-of-direct-oral-anticoagulants-and-antiplatelet-agents-among-patients-with-venous-thromboembolism-a-population-based-multinational-cohort-study/. Accessed November 29, 2023.
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