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Abstract

Background: Injectable opioid agonist treatment (iOAT) with diacetylmorphine and hydromorphone is an option for people with opioid use disorder who have not found that other treatments sufficiently meet their needs. Even though regulatory approval was granted almost a decade ago, iOAT remains inadequately integrated into the continuum of care. While evidence shows its success in driving treatment engagement, the absence of recent real-world data on cost structure and process of providing care may limit its broader adoption in British Columbia (BC). This thesis aims to develop an interactive costing tool, which will help optimize treatment costs and better understand the cost structure of a typical iOAT program. Methods: A narrative literature review was conducted, which revealed that time-driven activity-based costing (TDABC) is the method best aligned with the objectives of the study. Data on the care pathway, including time and disposable items were collected at iOAT clinics (N = 4) across BC. Interrater reliability was evaluated through Intraclass Correlation Coefficient (ICC) with a two-way random effects ANOVA based on an absolute agreement, single-rater model. Time data were logarithmically transformed, and logarithmic mean and standard deviation were calculated and simulated (N = 10,000) using Monte Carlo probabilistic sensitivity analysis. A process map was created to illustrate the care pathway. Additional insights on clinic workflows and perspectives on cost optimization were gathered through questionnaires (N = 10). Results: Strong interrater reliability was achieved across all four observations (ICC: 0.89, 0.95, 0.94, 0.97). The process map captured how care is provided in real-world settings. Scenario analyses revealed that the annual cost of iOAT per client can range from $11,635.60, 95% CI [$8,893.70-$19,823.73] to $81,506.44, 95% CI [$71,960.17-$109,114.86] for DAM and $45,688.34, 95% CI [$40,204.54-$62,064.59] to $70,249.91, 95% CI [$60,703.64-$97,858.33] for HDM. Providers identified waste minimization and building capacity for team-based delivery as methods to reduce expenditures. An interactive costing tool was developed, integrating findings from observations, public cost data, and questionnaires. Conclusions: As the first standalone microcosting exercise for iOAT based on real-world data, this study provided an interactive costing tool, which can inform efforts to make iOAT more broadly available across BC.