The National Roundtable on Evaluation of Multilevel/Combination HIV Prevention Interventions had the goals of examining the present state of the art of multilevel and combination HIV prevention interventions, both domestically and internationally; to define the significant challenges and scientific gaps in current evaluation methods and identify the most promising methodological approaches to address these gaps; and to guide the future agenda for HIV prevention research.
To address these methodological gaps, we must combine the methodological and statistical rigor associated with clinical trials, the conceptual framework of implementation science, the on-the-ground strategies of programmatic monitoring and evaluation, and the strengths of pre- and post-intervention mathematical modeling.
In looking at the HIV epidemic in the US, the group discussed current initiatives guided by the National HIV/AIDS Strategy and the increased optimism over treatment as prevention. We noted that considerable progress has been made in developing core metrics to evaluate outcomes along the “treatment-as-prevention cascade” that could be captured through public health surveillance—number of new HIV cases detected and proportion linked to care, retained in care, on active treatment, and virally suppressed. Our understanding of the optimum package of interventions with regard to both effectiveness and efficiency remains incomplete. Progress was reported, however, in the collection of process data at the local level to better assess how to improve programs. Devising epidemic impact measures to quantify reductions in HIV incidence attributable to combination interventions remains challenging, mostly due to barriers to testing impact through methods like community cluster randomization in the US.
Looking globally, the group discussed a number of planned clinical trials of combination interventions also spurred by optimism over treatment as prevention. Common elements of combination approaches included expansion of voluntary counseling and testing, adult male circumcision, prevention of mother-to-child transmission, and management of sexually transmitted infections, along with expanding ART treatment. Outcome measures were generally framed in terms of the treatment-as-prevention cascade, though these data are not available from current surveillance systems, pointing to the need to create improved systems of data collection. The most common approach to measuring epidemic impact was clustered community randomization, with incident infections measured through cohorts or newer cross-sectional, multi-assay algorithms.
Recommendations from the roundtable include the following:
- A new coalition of interventionists, implementation scientists, public health program and surveillance specialists, mathematical modelers, and behavioral scientists is needed to adequately address the evaluation of multilevel/combination HIV interventions at the community-level.
- The use of the conceptual frameworks of the HIV prevention continuum and engagement-in-HIV-care cascade should be used in structuring evaluation of combination HIV interventions.
- Common public health surveillance systems to evaluate combination HIV prevention interventions at the community level are recommended, and this capacity should be further developed internationally.
- Mathematical modeling before, during, and after multilevel/combination HIV interventions should be incorporated in the design, implementation, and interpretation of intervention results.
- Because an emphasis on efficiency as well as effectiveness from implementation science is helpful, costing and cost-effectiveness evaluations of combination HIV prevention interventions are recommended and are important to policy makers.
- Use of innovative trial and observational study designs outside of the traditional randomized, controlled trial paradigm should be used to account for the complex multilevel and combination nature of new HIV prevention interventions, and emerging design and analysis methods (e.g., stepped-wedge designs, adaptive trial designs, causal inference modeling of “natural experiments”) should be considered to address the challenges of community-level effectiveness evaluation.
- Because social factors and human behaviors are integral factors all along the HIV care and treatment cascade, it is crucial to include social and behavioral science in the design, implementation, and evaluation of combination interventions (e.g., community engagement and mobilization interventions).
- Mixed methods, including qualitative data collection (e.g., key informant interviews with implementers, in-depth interviews with target population members), are recommended to increase our understanding of how and why interventions are successful or not.
- Increased funding opportunities for methods development, whether as standalone projects or as supplements to large trials, is recommended as is funding for career development in methods research (e.g., methods-focused K awards).