Safety and Efficacy of Warfarin Therapy in Remote Communities of the Top End of Northern Australia

Background Warfarin remains a widely used anticoagulant but application in the remote context is not well documented. This study aimed to assess in more detail whether warfarin is being utilised effectively in Australia's most isolated and remote areas. Methods Retrospective cohort analysis of 2013 captured international normalised ratio (INR) results from people engaged in long term warfarin usage within a number of remote Northern Australian communities. Assessment of monitoring, effectiveness of dosing and complication rates was undertaken. Results A cohort of 167 patients was established. On average, warfarin was utilised within therapeutic range 52% of the time. Monitoring frequency averaged 16 days. Major bleeding and thrombo-embolism occurred at rates of 5.8 and 4.1 per 100 patient years respectively. Conclusions Therapeutic utilisation of warfarin in this setting is close to accepted rates but has room for improvement. Monitoring was acceptable and complication rates were not disproportionately high. This study indicates that warfarin is being used with reasonable safety and efficacy in remote regions, but further research is needed.