Measuring the importance of different barriers to opioid agonist treatment using best-worst scaling in an Australian setting.

Objective: Opioid agonist treatment (OAT) is an effective treatment for opioid use disorder (OUD), however several client barriers to OAT are reported. Client importance of these barriers using economic preference elicitation measures have not been identified. This paper determines the most important OAT barriers using best-worst scaling (BWS) and compares the results of BWS to Likert scale.

Methods: Cross-sectional self-completed survey with 191 opioid dependent clients who attended Australian needle and syringe sites. Participants were presented 15 Likert scale barriers and 15 BWS barrier scenarios. The BWS data was presented using count analysis, multinomial logit and mixed logit models. The ranking of barrier items was completed using three BWS methods and one Likert scale method, with share preference results (BWS) or mean scores (Likert) used to rank the 15 barriers.

Results: The most important client barriers were 'enjoy using opioids', 'lack of support services' and 'hard to access'. The four ranking methods produced different barrier rankings for the most important barriers, but similar results for the least important barriers.

Conclusion: Policies around OAT as a harm reduction approach, increased support services and increased availability of OAT services would be beneficial in improving OAT uptake. Comparing BWS and Likert methods produced different highest ranked barriers, indicating the method used to identify preferences has significant implications on the type of intervention prioritised.