Participants will be randomly assigned to one of 16 experimental conditions. Each condition will represents every possible combination of 4 components (e.g., 1-4, 2-4, 4 only). Participants complete a survey assessment at baseline, complete their assigned intervention components, and then return to complete follow-up assessment surveys at 3-, 6-,9-, and 12-months. The primary outcome is sustained viral suppression defined as viral load test results of <400 copies per mL on all 6-,9-, and 12-month follow-up visits. Results of Aim 1 will yield estimates of the unique impact of each intervention component, as well as each combination of components, on sustained viral suppression. The research team and partners will make decisions about what constitutes the optimized intervention by judging the observed effect sizes and statistical significance against real-world constraints that go into the delivery of the interventions. The secondary aims are to test mediators to explain component 1-4 and its relationship to viral suppression. We will also test moderators of these relationship between each component and outcome of viral suppression.
The study will test four behavioral intervention components to identify the combination of the four components that best supports people who inject drugs to achieve and sustain HIV viral load suppression.~The study design is a 2-to-the-4 factorial experiment. The 2 represents the level of each component: 0 (receive) or 1 (don't receive). The 4 represents the number of components being tested. The four components are: 1) receiving (or not receiving) peer support services for medication-assisted treatment (MAT) uptake and persistence, 2) behavioral activation therapy for depression (BAT), 3) Life-Steps Program for medication adherence, and 4) patient navigation for HIV care. Therefore, in order to test which combination of components produce the best outcome, this factorial design randomizes people to 1 of 16 conditions. Each condition represents a possible combination of the 4 components above.