Rapid and substantial increases in anticoagulant use and expenditure in Australia following the introduction of new types of oral anticoagulants

Abstract

Objectives To quantify changes in anticoagulant use in Australia since the introduction of Non-vitamin K antagonist anticoagulants (NOACs) and to estimate government expenditure.

Design Interrupted-time-series analysis quantifying anticoagulant dispensing, before and after first Pharmaceutical Benefits Scheme (PBS) NOAC listing in August 2009 for venous thromboembolism prevention; and expanded listing for stroke prevention in non-valvular atrial fibrillation (AF) in August 2013, up to June 2016. Estimated government expenditure on PBS-listed anticoagulants.

Setting and participants PBS dispensing in 10% random sample of Australians, restricted to continuous concessional beneficiaries dispensed oral anticoagulants from July 2005 to June 2016. Total PBS anticoagulant expenditure was calculated using Medicare Australia statistics.

Main outcome measures Monthly dispensing and initiation of oral anticoagulants (warfarin, rivaroxaban, dabigatran or apixaban). Annual PBS anticoagulant expenditure.

Results An estimated 149,180 concessional beneficiaries were dispensed anticoagulants (100% warfarin) during July 2005. This increased to 292,550 during June 2016, of whom 47.0%, 27.1%, 18.7% and 7.2% were dispensed warfarin, rivaroxaban, apixaban and dabigatran, respectively. Of 16,500 initiated on anticoagulants in June 2016, 24.3%, 38.2%, 30.0% and 7.5% were initiated on warfarin, rivaroxaban, apixaban, and dabigatran, respectively. Compared to July 2005-July 2013, from August 2013-June 2016, dispensings for all anticoagulants increased by 2,303 dispensings/month (p<0.001, 95%CI = [1,229 3,376]); warfarin dispensing decreased by 1,803 dispensings/month (p<0.001, 95%CI = [–2,606, –1,000]). Total PBS anticoagulant expenditure was $19.5 million (97.0% concessional) in 2008/09, of which 100% was warfarin and $203.3 million (86.2% concessional) in 2015/16, of which 11.2% was warfarin.

Conclusions The introduction of the NOACs led to substantial increases in anticoagulant use and expenditure in Australia.