Effect of expanding opioid agonist therapies on the HIV epidemic and mortality in Ukraine: a modelling study

Abstract

Background: As HIV incidence and mortality continue to increase in eastern Europe and central Asia, particularly among people who inject drugs (PWID), it is crucial to effectively scale-up opioid agonist therapy (OAT), such as methadone or buprenorphine maintenance therapy, to optimise HIV outcomes. With low OAT coverage among PWID, we did an optimisation assessment using current OAT procurement and allocation, then modelled the effect of increased OAT scale-up on HIV incidence and mortality for 23 administrative regions of Ukraine.

Methods: We developed a linear optimisation model to estimate efficiency gains that could be achieved based on current procurement of OAT. We also developed a dynamic, compartmental population model of HIV transmission that included both injection and sexual risk to estimate the effect of OAT scale-up on HIV infections and mortality over a 10-year horizon. The compartmental population model was calibrated to HIV prevalence and incidence among PWID for 23 administrative regions of Ukraine. Sources for regional data included the SyrEx database, the Integrated Biological and Behavioral Survey, the Ukrainian Center for Socially Dangerous Disease Control of the Ministry of Health of Ukraine, the Public Health Center of the Ministry of Health of Ukraine, and the Ukrainian Census.

Findings: Under a status-quo scenario (OAT coverage of 2·7% among PWID), the number of new HIV infections among PWID in Ukraine over the next 10 years was projected to increase to 58 820 (95% CI 47 968-65 535), with striking regional differences. With optimum allocation of OAT without additional increases in procurement, OAT coverage could increase from 2·7% to 3·3% by increasing OAT doses to ensure higher retention levels. OAT scale-up to 10% and 20% over 10 years would, respectively, prevent 4368 (95% CI 3134-5243) and 10 864 (7787-13 038) new HIV infections and reduce deaths by 7096 (95% CI 5078-9160) and 17 863 (12 828-23 062), relative to the status quo. OAT expansion to 20% in five regions of Ukraine with the highest HIV burden would account for 56% of new HIV infections and 49% of deaths prevented over 10 years.

Interpretation: To optimise HIV prevention and treatment goals in Ukraine, OAT must be substantially scaled up in all regions. Increased medication procurement is needed, combined with optimisation of OAT dosing. Restricting OAT scale-up to some regions of Ukraine could benefit many PWID, but the regions most affected are not necessarily those with the highest HIV burden.

Funding: National Institute on Drug Abuse.

Figure 1:

Modeling Opioid Agonist Treatment Optimization and Scale up Regionally in Ukraine Legend: Modeling Scenarios A. Current OAT coverage based on observed levels of OAT enrollment (grey); B. Optimization gain using no additional procurement for the country, but with optimal dosing allocations, treatment entry and retention strategies (black); C. Scaling up OAT coverage to 20% in each region (orange).

Figure 2:

Number of Deaths Averted Nationally and in Each Region of Ukraine Over 10 Years

Figure 3:

Number of HIV Infections Averted Nationally and in Each Region of Ukraine Over 10 years

Figure 4.

Number of Deaths and HIV Infections Averted per Additional OAT Slot in a 20% Scale-up Scenario

Figure 5:

Model Schematic HIV Transmission model. Note: The model is stratified by 3 population groups: Heterosexual Men, Heterosexual Women, MSM (See model in appendix for complete details)