Aim 1: Formative work guided by an implementation mapping process to engage key stakeholders, finalize implementation strategies to maximize successful implementation of the evidence-informed clinical intervention, and develop site specific adaptations of the interventions along with an implementation blueprint to guide intervention delivery. Proposed implementation strategies include 1) identify and prepare referral site champions, 2) audit and feedback for referral sites, 3) build a coalition between referral and study care sites, 4) assess for readiness and identify of implementation barriers at care sites, 5) adaptation of intervention components to site-specific context, 6) develop a formal implementation blueprint to guide site-specific intervention delivery, 7) develop educational materials and conduct ongoing training at each site to support implementation fidelity, and 8) create a learning collaborative to facilitate cross-site sharing of best practices and positive peer pressure.
Aim 2: Following initial formative work, a type 2 hybrid implementation-effectiveness study will be conducted using a prospective cohort of persons referred to drop-in/mobile HIV care at one of the four participating care sites (n=400). Patients are eligible for referral to the drop-in/mobile care model if they meet the following three criteria: 1) most recent HIV viral load \>200 copies/mL or off ART by ≥1 month by self-report; 2) sub-optimal care engagement by self-report or chart history (defined as no current HIV primary care provider, no HIV primary care visit in the past 6 months, or ≥ 1 missed HIV primary care visit in the past 6 months); and 3) ≥1 major barrier to care engagement by self report, chart history, or clinical assessment (homelessness/unstable housing, any mental health diagnosis, any illicit substance use). The study will compare outcomes over 12 months to two propensity score-matched control groups: 1) contemporaneous patients identified using Alameda and San Francisco Departments of Public Health (DPH) HIV surveillance data (n=400) and 2) historical patients at participating clinic sites (n=400). The evaluation will be guided by the RE-AIM implementation framework, with co-primary outcomes of Reach (≥ 1 HIV primary care visit over 12 months following referral) and Effectiveness (≥1 HIV viral load \<200 copies/mL over 12 months following referral).
In Aim 3: Impact Analysis to understand and model the individual, clinic, and population-level impacts of the staged care approach, the study will use several approaches: 1) Heterogeneity and Health Equity Analysis, 2) Pathway \& Scenario Analysis, 3) Cost and Cost-effectiveness Analysis, and 4) Population-level Health Impact Modeling. Analyses will use mixed-methods to assess for whom the staged care approach worked and did not work and why. The Cost and Cost-effectiveness Analysis will estimate total program costs, costs associated with each intervention strategy, cost per person referred, cost per person engaged in each intervention strategy and cost per person engaged in optimized pathways. Observed study outcomes and scenario analysis results will be used to estimate the additional number of patients with suppressed viral load within the entire program, for each intervention strategy and for the identified optimized pathways.
