Impact of guidance issued during COVID-19 to expand take-home doses of opioid agonist treatment (OAT) in Ireland: a population-based analysis of prescribing practices and patient outcomes 2018 to 2023

Emergency contingency guidelines for opioid agonist treatment (OAT), recommending the relaxation of take-home dosing, were introduced in Ireland in March 2020, to ensure uninterrupted access to treatment while mitigating COVID-19 risk. While, the 2020 Programme for Government in Ireland made a commitment to retaining COVID-19 measures to improve access to OAT, we do not know to what extent prescribing practices for take-home doses of OAT changed following the introduction of the emergency guidelines, or whether changes were sustained as public health restrictions relaxed. Furthermore, we do not know how changes in prescribing practices for take-home doses of OAT, sustained or otherwise, affected patient outcomes such as treatment dropout (a high risk period for mortality) and overdose deaths. This study aims to evaluate the impact of guidance issued during COVID-19, to expand take-home doses of methadone or buprenorphine to patients with opioid use disorder in Ireland, on prescribing practices for opioid agonist treatment (OAT), treatment discontinuation and methadone-related deaths. The proposed programme of research will involve three inter-related studies, comprising quasi-experimental interrupted time series, a retrospective cohort study and a repeated cross-sectional study, primarily using data on methadone and buprenorphine prescriptions dispensed to individuals in Primary Care in Ireland, held by the HSE Primary Care Reimbursement Service, along with data from the National Drug Related Death Index (NDRDI), an epidemiological database, which records all poisoning deaths by drugs and/or alcohol in Ireland. The proposed study seeks to address an important knowledge gap, and in doing so has the potential to strengthen evidence-informed and outcomes-focused practice, services, policies and strategy, which was identified as a strategic priority in the mid-term review of the National Irish Drug Strategy 2021. This programme of research will also inform international policy discussions in relation to the relaxation of OAT take-home dosing.