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Type: Journal article
Title: Comparative effectiveness and safety of low-strength and high-strength direct oral anticoagulants compared with warfarin: a sequential cohort study
Author: Pratt, N.
Ramsay, E.
Kalisch Ellett, L.
Duszynski, K.
Shakib, S.
Kerr, M.
Caughey, G.
Roughead, E.
Citation: BMJ Open, 2019; 9(5):e026486
Publisher: BMJ Open
Issue Date: 2019
ISSN: 2044-6055
Statement of
Nicole L Pratt, Emmae Ramsay, Lisa M Kalisch Ellett, Katherine Duszynski, Sepehr Shakib, Mhairi Kerr, Gillian Caughey, Elizabeth Ellen Roughead
Abstract: OBJECTIVES:The aim of this study was to compare effectiveness and safety of low-strength and high-strength direct oral anticoagulants (DOACs) with warfarin in the Australian Veteran population. DESIGN:Sequential cohort study using inverse probability of treatment weighting (IPTW) and propensity score matching. Initiators of high-strength (apixaban 5 mg, dabigatran 150 mg, rivaroxaban 20 mg) and low-strength DOACS (apixaban 2.5 mg, dabigatran 110 mg, rivaroxaban 15 mg) were compared with warfarin initiators. SETTING:Australian Government Department of Veterans' Affairs claims database. PARTICIPANTS:4836 patients who initiated oral anticoagulants (45.8%, 26.0% and 28.2% on low-strength, high-strength DOACs and warfarin, respectively) between August 2013 and March 2015. Mean age was 85, 75 and 83 years for low-strength, high-strength DOACs and warfarin initiators, respectively. MAIN OUTCOME MEASURES:One-year risk of hospitalisation for ischaemic stroke, any bleeding event or haemorrhagic stroke. Secondary outcomes were 1-year risk of hospitalisation for myocardial infarction and death. RESULTS:Using the IPTW method, no difference in risk of ischaemic stroke or bleeding was found with low-strength DOACs compared with warfarin. As a class, no increased risk of myocardial infarction was found for low-strength DOACs, however, risk was elevated for apixaban (HR 2.25, 95% CI 1.23 to 4.13). For high-strength DOACs, no difference was found for ischaemic stroke compared with warfarin, however, there was a significant reduction in risk of bleeding events (HR 0.63, 95% CI 0.44 to 0.89) and death (HR 0.40, 95% CI 0.28 to 0.58). Propensity score matching showed no difference in risk of ischaemic stroke or bleeding. CONCLUSION:We found that in the practice setting both DOAC formulations were similar to warfarin with regard to effectiveness and had no increased risk of bleeding.
Keywords: atrial fibrillation; bleeding; medication safety; oral anticoagulants; warfarin
Rights: © Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http:// creativecommons. org/ licenses/ by- nc/ 4. 0/.
RMID: 0030114732
DOI: 10.1136/bmjopen-2018-026486
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