To describe temporal trends in appropriate antithrombotic therapy use in hospitalised atrial fibrillation (AF) patients and identify evidence-treatment gaps in clinical practice.

Retrospective cohort study from January 2009–March 2016.

Tertiary and secondary teaching hospitals in Perth, Western Australia.

Hospitalised adults with non-valvular AF.

We identified 11,294 index AF admissions, with a mean age of 76.9 years, 45.8% women and 86.3% at high risk of stroke (CHA₂DS₂-VASc score ≥2 in men and ≥3 in women). In high risk subjects use of appropriate antithrombotic therapy improved over time with increasing oral anticoagulant (OAC) use and declining sole antiplatelet use (both trend p<0.001). However, by study end only 45.3% of high-risk patients were receiving OAC therapy. In low risk patients, receipt of OAC therapy was steady throughout the study at 40.5% (trend p=0.10). The gender gap in OAC use narrowed over time, with no significant difference between high risk men and women by study end. Use of OAC therapy in elderly patients (age ≥75 years) remained lower than younger patients (age <65 years) over the entire period, with only 31% of elderly patients receiving OAC therapy at study end. From 2012 onwards use of non-vitamin K oral anticoagulants (NOACs) doubled each year with declining warfarin use (both trend p<0.001).

Despite substantial uptake of NOACs, OAC therapy in AF patients at high risk of stroke remains under-utilised in Western Australia and over-utilised in low risk patients. Further work is required to reduce treatment-risk mismatch for stroke prevention in AF patients.