Missed Opportunities to Initiate Oral Anticoagulant in Atrial Fibrillation: Insights from Australian Acute Coronary Syndrome Registries

Background: Many patients with atrial fibrillation (AF) do not receive oral anticoagulant (OAC) therapy. The aims of this study were to 1) document receipt of OAC among patients with a history of AF admitted with an acute coronary syndrome (ACS); and to 2) determine whether hospital admission was associated with an improvement in prescription of OAC therapy. Methods: Using Australian data from the Cooperative National Registry of Acute Coronary Care, Guideline Adherence and Clinical Events (CONCORDANCE) and Global Registry of Acute Coronary Events (GRACE) registries, 1,479 patients with a history of AF presenting with an ACS were separated into two groups: aspirin monotherapy/no therapy (No OAC) or oral anticoagulant ± aspirin (OAC). Clinical characteristics and in-hospital treatments and outcomes were compared. Results: Of 1,479 patients, 532 (36%) with a history of AF presented on OAC with the remainder receiving antiplatelet (n=580 [39%]) or no antithrombotic therapy (n=367 [25%]). Treatment with OAC prior to presentation increased during the 18 years of the study (27% to 56%, p=0.0002). Ninety-five per cent (95%) of the OAC group had a CHA2DS2-VA score >1 vs 88% of the No OAC group (p<0.001). Patients receiving OAC had a lower prevalence of bleeding risk factors than no OAC patients (p<0.001). Only 39% of this cohort was discharged on an OAC, although this increased during the observational period (26–61%, p≤0.0001). Conclusion: In patients presenting with an ACS with a history of AF, receipt of OAC has improved over time but remains suboptimal. There is minimal escalation in provision of OAC therapy during hospital care, indicating missed opportunities to address this evidence practice gap.