Background: Advanced age is an important risk factor for venous thromboembolism (VTE), recurrent VTE and related mortality. Moreover, older adults have a higher risk of anticoagulant related bleeding. However, the effects of direct oral anticoagulants (DOACs) among octogenarian patients with VTE remain poorly understood, complicating the benefit-risk assessment of VTE treatment in this age group.
Aims: To assess the effectiveness and safety of DOACs compared to vitamin K antagonists (VKAs) among octogenarians with VTE.
Methods: We conducted an international cohort study using administrative healthcare databases from the Canadian province of Québec and Germany. We assembled two population-based cohorts of octogenarians with incident VTE initiating treatment with DOACs or VKAs 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 (Québec: 12/2016; Germany: 12/2019). Using an as-treated exposure definition, we compared DOACs to VKAs, thereby applying inverse probability of treatment weighting based on high-dimensional propensity scores 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. Sensitivity analyses addressed the potential for different sources of bias.
Results: Our cohort included 6,737 octogenarians with VTE (Québec: n=2,556; Germany: n=4,181) who initiated use of DOACs (n=3,778) or VKAs (n=2,959). Compared to VKAs, DOACs were associated with similar risks of recurrent VTE (weighted HR, 0.80; 95% CI, 0.43-1.46; I2=0.00), major bleeding (weighted HR, 0.96; 95% CI, 0.57-1.63; I2=0.59), and all-cause mortality (weighted HR, 1.04; 95% CI, 0.81-1.34; I2=0.00). Sensitivity analyses yielded findings consistent with those of the primary analysis.
Conclusion(s): Among octogenarians with VTE, DOACs showed a comparable effectiveness and safety compared with VKAs. Our results support the use of DOACs in this high-risk group.
To cite this abstract in AMA style:Douros A, Basedow F, Cui Y, Dimakos J, Walker J, Enders D, Tagalakis V. Effectiveness and safety of direct oral anticoagulants among octogenarians with venous thromboembolism: an international multi-database cohort study [abstract]. https://abstracts.isth.org/abstract/effectiveness-and-safety-of-direct-oral-anticoagulants-among-octogenarians-with-venous-thromboembolism-an-international-multi-database-cohort-study/. Accessed August 16, 2022.
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