Methadone maintenance therapy service components linked to improvements in HIV care cascade outcomes: A systematic review of trials and observational studies.

BACKGROUND: The beneficial links between engagement in methadone maintenance therapy (MMT) and HIV treatment outcomes have been extensively described. Nevertheless, people who use drugs (PWUD) continue to experience suboptimal HIV treatment outcomes. In this systematic review, we sought to identify components of MMT service provision that are associated with improvements in HIV care outcomes across the HIV care cascade.

METHODS: We searched for peer-reviewed studies in online databases. To be eligible for inclusion in this review, studies must have involved a population or sub-population of PWUD engaged in MMT; report improved uptake of HIV testing, exposure to ART, or HIV-1 RNA plasma viral load suppression; provide details on MMT services; and be published in English between 1 January 2006 until 31 December 2018.

RESULTS: Out of the 5594 identified records, 22 studies were eligible for this systematic review. Components of MMT services associated with HIV care cascade outcomes described in the studies were classified in three categories of care models: 1) standard MMT care with adequate doses, 2) standard MMT care and alongside additional medical component(s), and 3) standard MMT care, additional medical component(s) as well as informational or instrumental social support.

CONCLUSION: The few studies identified reflect a scarcity of evidence on the role of social support to increase the benefits of MMT for PWUD who are living with HIV. Further research is needed to assess the role of medical and social service components in MMT care delivery in advancing PWUD along the HIV care cascade.