Direct oral anticoagulant prescribing for atrial fibrillation: an Australian tertiary centre experience of ischaemic stroke complication

BACKGROUND: Direct oral anticoagulants (DOACs) have changed the paradigm of atrial fibrillation (AF) management in preventing ischaemic cerebrovascular accidents (CVAs). They are safe and effective in this aim. Their dosing is simpler than the vitamin K antagonist warfarin; however, there are certain nuances in dosing adjustments which clinicians must be aware of before initiating changes. AIM: We sought to investigate the role of inappropriate DOAC underdosing in contributing to the development of ischaemic CVAs. METHODS: A retrospective cohort study was performed on all ischaemic CVA presentations to an Australian tertiary centre in the 12 months of 2023. We analysed all those already on DOAC therapy and the significance of inappropriate DOAC underdosing. This was compared to all DOAC prescriptions, without associated ischaemic CVA complication, within the centre during the same period and whether underdosing played a significant role. RESULTS: Seventy-two patients presented to our centre with an ischaemic CVA, already prescribed and taking DOAC therapy. Underdosing of DOAC therapy, away from established guidelines, was the most common attributable factor found. Underdosing of DOACs had an overall odds ratio of 4.31, with a 95% confidence interval (95% CI) of 2.49-7.46, of suffering an ischaemic CVA. The periprocedural period was also found to be high risk for patients undergoing DOAC therapy. CONCLUSIONS: Underdosing of DOAC therapy has a significant impact on whether individuals develop ischaemic CVAs. Clinicians must be stringent in applying dose reductions based on established guidelines and must be aware to review dosing for all their DOAC patients.