Evaluation of the effect of direct oral anticoagulant availability on hospital presentations for bleeding related to oral anticoagulation in South Australia

Background: Direct oral anticoagulant drugs (DOACs) are known to improve clinical outcomes and decrease bleeding rates compared with warfarin. The effect of the introduction of DOACs into Australian general prescribing practice on anticoagulant-related hospital presentations related to bleeding is unknown. Aim: This study compared the rate of anticoagulant-related hospital presentations related to bleeding for DOACs and warfarin in South Australia. Methods: A retrospective observational cohort study across metropolitan tertiary hospitals identified hospital presentations related directly to an anticoagulant bleeding event. Presentation rates were calculated against prescribing quantities from Pharmaceutical Benefits Scheme data. Data were collected across two periods: January–June 2013 (warfarin-only prescribing) and January–June 2015 (combined warfarin and DOAC prescribing). The main outcome measure was the number of hospital presentations per 100 patient-years of prescribed anticoagulant therapy. Results: For the total study period, the overall hospital presentation rate for any DOAC use was 0.52 per 100 patient-years, compared with 1.51 per 100 patient-years for warfarin (incidence rate ratio 2.89; 95% confidence interval 2.02–4.12; p < 0.001). One hospital presentation was associated with each 67 years of warfarin use, and 192 years of DOAC use. The mean cost associated with warfarin and DOAC hospital presentations was similar ($3705 and $3671 respectively; p = 0.69). There were a further 0.28 presentations per 100 patient-years for the management of supratherapeutic International Normalised Ratios in warfarin users, at a cost of $3233 per episode. Conclusion: The use of DOACs in general practice in the Australian setting is associated with decreased anticoagulant-related hospital presentations for bleeding.