Decreasing international HIV transmission: the role of expanding access to opioid agonist therapies for injection drug users.

Aims: To examine the role of expanded access to opioid agonist treatment as a means to decrease international HIV transmission.

Design: Review of the English language literature via Medline.

Measurements: Estimates of prevalence rates for injection drug use, HIV infection and treatment effect sizes for changes in opioid use, opioid injection, needle-sharing, injection-related HIV risk behavior and cost.

Findings: An estimated 12.6 million injection drug users internationally accounted for 10% of the 4.2 million new HIV infections in 2003. Ninety-three of the 136 countries (68%) that report injection drug use identify HIV infection related to this behavior. Observational studies of methadone treatment demonstrate decreases in opioid use, opioid injection, needle-sharing and lower rates of HIV prevalence and incidence. The effectiveness of buprenorphine in demonstrating similar findings is expected, although implementations and research are still emerging. The cost-effectiveness of opioid agonist treatment has been established. The barriers to international adoption of opioid agonist treatment, despite the research evidence and international guidelines, are discussed.

Conclusions: Untreated opioid dependence leads to HIV transmission, on an international level. Opioid agonist treatments are associated with reductions in the frequency of opioid use, fewer injections and injection-related HIV risk behaviors and lower rates of HIV prevalence and incidence. Despite international recommendations, treatment for opioid-dependent injection drug users with methadone and buprenorphine is limited. Research, implementation efforts and political strategies to expand access to opioid agonist treatment are needed in order to combat the spread of HIV, especially in the developing world.