Time trends in stroke risk management among high-risk patients with non-valvular atrial fibrillation in Australia between 2011-2019

Background: Atrial fibrillation (AF) is associated with stroke. Major changes to AF management recommendations in 2016-2018 advised that: 1. Stroke risk be estimated using the CHA₂DS₂-VA score; 2. Antiplatelet agents (APAs) do not effectively mitigate stroke risk; 3. Anticoagulation is prioritised above bleeding risk among high-risk patients; and 4. Non-vitamin K oral anticoagulants (NOACs) are used as first-line anticoagulants.

Aim: To examine trends in stroke risk management among high-risk patients with non-valvular AF in Australia between 2011-2019.

Method: De-identified data of patients were obtained from 164 separate general practices. Data included information on patient demographics, diagnoses, health risk factors and recent prescriptions. Patients with a diagnosis of non-valvular AF were identified and stroke risk was calculated by CHA₂DS₂-VA score. High risk patients (i.e. CHA₂D_S2-VA ≥ 2) were categorised as being managed by oral anticoagulants (OACs, i.e., warfarin or NOACs), APAs only, or neither (i.e., no OACs or APAs) and time trends in prescribing were examined. Multivariate analyses examined the characteristics of patients receiving the guideline recommended OAC management.

Results: Data were available for 337,964 patients; 8696 (2.6 %) had AF. Most patients with AF (85.8 %, n = 7116) had high stroke risk. The proportion of high-risk patients managed on OACs increased from 56.7 % in 2011 to 73.7 % in 2019, while the proportion prescribed APAs declined from 31.1 % to 14.0 %. Those receiving neither treatment remained steady (around 12 %). Overall, 26.3 % of patients were inadequately anticoagulated at the end of the study period. There were no age or gender differences in receiving the guideline-recommended therapy, and patients with comorbidities associated with increased stroke risk were more likely to receive OAC therapy.

Conclusions: Stroke risk management among patients with AF has improved between 2011-2019, however there is still scope for further gains as many high-risk patients remain inadequately anticoagulated. Better stroke risk assessment by clinicians coupled with addressing practitioner concerns about bleeding risk may improve management of high-risk patients.