Unit costs of opioid agonist therapy: a global systematic review and cost extrapolation

People who inject drugs (PWID) face elevated risks of HIV and viral hepatitis transmission. Opioid agonist therapy (OAT) like methadone and buprenorphine reduce drug-related harms and improve health outcomes among PWID. Despite effectiveness, global OAT coverage remains suboptimal. This study estimated the global unit cost of OAT provision to inform resource allocation and scale-up of harm reduction services.

We conducted a systematic review to identify cost estimates of OAT provision and cost drivers. Data were extracted from peer-reviewed and grey literature sources. Mixed-effects multivariable regression models, incorporating country-level and program-level covariates, were developed to predict OAT unit costs. The best performing model was used to extrapolate the monthly per person costs of providing OAT in 210 countries.

We identified 175 cost estimates across 32 countries. Most estimates were from high-income countries. Higher unit costs were associated with higher country log GDP per capita, more program components, and inclusion of ancillary services in the cost estimations. The best-performing model predicted cost within 95% prediction intervals for 27 out of 32 countries when using the full dataset.

The study highlights the scarcity of OAT cost data, particularly in low-income countries, and underscores the need for more research in diverse settings to improve the accuracy and generalizability of cost estimates. This study provides estimates of OAT unit costs, offering insights for policymakers to optimize resource allocation and expand harm reduction efforts.