Pharmacoeconomic analysis of opioid substitution therapy as a tool for HIV infection prevention in Ukraine

Opioid substitution therapy (OST) with methadone- or buprenorphine-based opioid agonist medicines is the primary treatment for opioid dependence and an important component of HIV prevention among people who inject drugs (PWID). This study aimed to provide a pharmacoeconomic rationale for expanding OST in Ukraine by assessing its effects on quality of life, health-system costs, and the prevention of new HIV infections. Materials and methods – Epidemiological data on the dynamics of HIV/AIDS among PWID in Ukraine for 2021–2025 (new cases, number of people living with HIV, mortality, and ART coverage) and National Health Service of Ukraine tariffs were used. Mathematical modelling of four epidemiological states was performed using Microsoft Excel and Python. The cost–utility analysis compared maintaining current OST coverage at 32,405 people (9.25 %) with immediately reaching the target coverage of 140,120 people (40 %) and maintaining this level throughout 2026–2030. The budget impact analysis modelled a phased expansion to 40 %. A four-state epidemiological model with monthly cycles was used. The relative risk of HIV infection while receiving OST was 0.46. Costs were based on National Health Service of Ukraine tariffs, while utility weights were derived by multiplicatively combining published estimates for HIV health states and OST participation. Predictive performance was assessed using rolling validation: the mean prediction error for new HIV infections was 12.57 %, while the error in reproducing the sizes of model states ranged from 0.42 % to 4.22 %. Expanding OST generated 122,696 additional discounted QALYs and required UAH 3,438.3 million in additional discounted costs; the incremental cost–utility ratio (ICER) was UAH 28,023/QALY. This value was below one gross domestic product per capita (UAH 131,944, based on the latest available official data for 2021), corresponding to the highest category of cost-effectiveness on the national scale. Immediate expansion prevented approximately 888 new HIV infections. The budget impact of phased expansion was UAH 1,848.7 million, with approximately 431 infections prevented. Direct quality-of-life improvement attributable to OST accounted for 99.93 % of the incremental QALYs. When this effect was reduced by 50 %, the ICER was UAH 56,011/QALY; when the effect was removed entirely, the ICER increased to UAH 45.27 million/QALY. The findings support expanding OST as a cost-effective treatment for opioid dependence, with an additional benefit in HIV prevention, while highlighting uncertainty surrounding utility weights.