11institutetext: Knowledge-based Systems and Document Processing Research Group Faculty of Computer Science Otto-von-Guericke-University Magdeburg 11email: [email protected] The effects of removing the requirement for prior reimbursement approval on anticoagulant use in Ireland: A cross sectional study.

Purpose: Prior approval for reimbursement is a cost containment policy, aimed at reducing demand. It has been employed in Ireland to address financial challenges due to the shift from warfarin to Direct Oral Anticoagulant (DOACs). Studies assessing the effectiveness of this policy are limited. Thus, we aimed to examine the effectiveness of prior approval for reimbursement of DOACs (apixaban, rivaroxaban) as a cost containment policy in Ireland. Methods: The Irish Health Service Executive-Primary Care Reimbursement Service database was used in this cross-sectional study. We examined the prescribing frequencies and associated costs of the oral anticoagulants; ((OACs) apixaban, rivaroxaban, and warfarin) listed in the top 100 most frequently prescribed drugs, between 2018 and 2021. Interrupted time series Poisson regression was used to assess the impact of removing the approval requirement of apixaban in September 2019 followed by the other DOACs in November 2020. Results: The prescribing frequency of OACs increased by almost 20% from 2018-2021. This study showed there were significant differences in the proportion of OACs prescribed among the Community Drug Schemes. A statistically significant decreased use of apixaban (<1%, p<0.05) occurred when prior approval was removed for all DOACs. Conclusions: The removal of prior approval for reimbursement of DOACs in Ireland had a minimal impact on the prescribing frequency trends of the OACs. Future use of these potentially useful policies by healthcare systems requires careful consideration of drug type, approval criteria and length of time the policy remains in place to minimise any negative effects associated with their use.