Adherence to direct or vitamin K antagonist oral anticoagulants in patients with atrial fibrillation: a long-term observational study.

Shahrzad Salmasi, Abdollah Safari, Mary A De Vera, Tanja Högg, Larry D Lynd, Mieke Koehoorn, Arden R Barry, Jason G Andrade, Marc W Deyell, Kathy L Rush, Yinshan Zhao, Peter Loewen

Journal: Journal of thrombosis and thrombolysis 2024;57(3):437-444

PMID: 38103148

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Abstract

Our objectives were to measure long-term adherence to oral anticoagulants (OACs) in patients with atrial fibrillation (AF) and to identify patient factors associated with adherence. Using linked, population-based administrative data from British Columbia, Canada, an incident cohort of adults prescribed OACs for AF was identified. We calculated the proportion of days covered (PDC) as a time-dependent covariate for each 90-day window from OAC initiation until the end of follow-up. Associations between patient attributes and adherence were assessed using generalized mixed effect linear regression models. 30,264 patients were included. Mean PDC was 0.69 (SD 0.28) over a median follow-up of 6.7 years. 54% of patients were non-adherent (PDC < 0.8). After controlling for confounders, factors positively associated with adherence were number of drug class switches, history of stroke or transient ischemic attack, history of vascular disease, time since initiation, and age. Age > 75 years at initiation, polypharmacy (among VKA users only), and receiving DOAC (vs. VKA) were negatively associated with adherence. PDC decreased over time for VKA users and increased for DOAC users. Over half of AF patients studied were, on average, nonadherent to OAC therapy and missed 32% of their doses. Several patient factors were associated with higher or lower adherence, and adherence to VKA declined during therapy while DOAC adherence increased slightly over time. To min im ize the risk stroke, adherence-supporting interventions are needed for all patients with AF, particularly those aged > 75 years, those with prior stroke or vascular disease, VKA users with polypharmacy, and DOAC recipients.

Address: Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver Campus, 2405 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.; Department of Mathematics, Statistics, and Computer Science, University of Tehran, Tehran, Iran.; Department of Data Analytics, Statistics and Informatics, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver Campus, 2405 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.; Centre for Health Evaluation & Outcome Sciences, Providence Health Care Research Institute, Vancouver, BC, Canada.; Department of Statistics, University of British Columbia, Vancouver, BC, Canada.; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver Campus, 2405 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.; Centre for Health Evaluation & Outcome Sciences, Providence Health Care Research Institute, Vancouver, BC, Canada.; School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada.; School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada.; Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.; UBC Center for Cardiovascular Innovation, Vancouver, BC, Canada.; Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.; School of Nursing, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada.; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver Campus, 2405 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada. [email protected].; UBC Center for Cardiovascular Innovation, Vancouver, BC, Canada. [email protected].

DOI: 10.1007/s11239-023-02921-8

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MeSH Terms: Adult, Humans, Atrial Fibrillation, Anticoagulants, Stroke, Ischemic Attack, Transient, Administration, Oral, Vitamin K