Anticoagulation use in rheumatic heart disease-associated atrial fibrillation: a study of real-world practice in Central Australia.

Background: Rheumatic heart disease (RHD) disproportionately impacts minority groups. Indigenous Australians living in remote areas such as Central Australia account for 3.8% of the population and 92% of RHD cases. A complication of RHD is valvular atrial fibrillation (vAF). Previous studies favour Vitamin K antagonist (VKA) use in vAF over direct oral anti-coagulants (DOACs). However, challenges to VKA use remain. This real-world retrospective observational study aimed to compare clinical outcomes between patients prescribed VKAs or DOACs for vAF in Central Australia over a five-year period. Methods: Patients with RHD and vAF on the Northern Territory RHD Register in January 2019 were identified and five-year outcome data collected. Patients were grouped and analysed according to prescribed oral anticoagulant therapy in January 2019 (intention to treat (ITT)) or in January 2024/time of event (as-treated analysis (AT)). The primary outcome was major adverse cardiac and cerebrovascular events (MACCE). The safety endpoint was major bleeding. Results: Of patients with vAF, 49 were included in the ITT analysis and 51 in the AT analysis. The mean age was 61.9 ± 13.9 years and 68.9 % were female. There was no difference in MACCE (25.0 % vs 22.2 %, p = 0.86) or major bleeding (20.0 % vs 11.1 %, p = 0.53) between VKAs and DOACs in the ITT analysis. Findings were similarly non-significant in AT analysis. Conclusion: This study demonstrates no significant advantage to VKA over DOAC therapy in vAF in a small cohort of RHD patients living in remote Australia. Further investigation is required to optimise treatment strategies in this important group.