Discontinuation of oral anticoagulation in atrial fibrillation and risk of ischaemic stroke.

Objective: To evaluate associations between oral anticoagulant (OAC) discontinuation and risk of ischaemic stroke (IS) among patients with atrial fibrillation (AF).
Methods: We undertook a population-based cohort study with nested case-control analysis using UK primary care electronic health records (IQVIA Medical Research Data-UK) and linked registries from the Region of Southern Denmark (RSD). Patients with AF (76 882 UK, 41 526 RSD) were followed to identify incident IS cases during 2016-2018. Incident IS cases were matched by age and sex to controls. Adjusted ORs for OAC discontinuation (vs current OAC use) were calculated using logistic regression.
Results: We identified 616 incident IS cases in the UK and 643 in the RSD. ORs for IS with any OAC discontinuation were 2.99 (95% CI 2.31 to 3.86, UK) and 2.30 (95% CI 1.79 to 2.95, RSD), for vitamin K antagonist discontinuation they were 2.38 (95% CI 1.72 to 3.30, UK) and 1.83 (95% CI 1.34 to 2.49, RSD), and for non-vitamin K antagonist oral anticoagulant discontinuation they were 4.59 (95% CI 2.97 to 7.08, UK) and 3.37 (95% CI 2.35 to 4.85, RSD). ORs were unaffected by time since discontinuation and duration of use. Annually, up to 987 IS cases in the UK and 132 in Denmark could be preventable if OAC therapy is not discontinued.
Conclusions: Our results suggest that patients with AF who discontinue OAC therapy have a significant twofold to threefold higher risk of IS compared with those who continue therapy. Addressing OAC discontinuation could potentially result in a significant reduction in AF-attributed IS.
Competing Interests: Competing interests: LAGR works for CEIFE, which has received other research funding from Bayer AG. LAGR has also received honoraria for serving on advisory boards for Bayer AG. DG has received honoraria from AstraZeneca (Sweden) for participation as a co-investigator on a research project outside the submitted work, and receiving speaker honorarium from Bristol-Myers Squibb outside the submitted work. YB and PV are employees of Bayer AG. GB is an employee of Bayer AB. MS has served on the steering committees and led sub-studies from trials sponsored by Bayer and has served as a consultant and received speaker’s honoraria from Bayer. MS has also served as a consultant to Portola, Bristol Myers Squibb and Janssen. LCS, SMH and JH report no potential conflicts of interest.
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