what is the risk of an ischaemic stroke if a patient with atrial fibrillation stops oral anticoagulant therapy (OAC)?

Last edited 01/2022 and last reviewed 03/2022

Considering what is the risk of an ischaemic stroke (IS) if a patient with atrial fibrillation stops oral anticoagulation therapy (OAC)?

A study investigating this question was undertaken (1):

  • 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
  • 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

Study authors concluded that (1):

  • patients with AF who discontinue OAC therapy have a significant two-fold to three-fold higher risk of IS compared with those who continue therapy
    • study suggests that patients who discontinued OAC therapy have a two- to three- fold higher IS risk than those who maintain therapy, irrespective of OAC class, time since discontinuation, or OAC duration

Reference:

  • Rodríguez LAG et al.Discontinuation of oral anticoagulation in atrial fibrillation and risk of ischaemic stroke.Heart Published Online First: 11 December 2020. doi: 10.1136/heartjnl-2020-317887.