Specifying Complex Relationships Among Facilitators and Barriers to PrEP Retention In Alabama and Mississippi Using a Feedback Perspective to Inform Intervention Adaptation

Background: Individuals who use PrEP for HIV prevention face psychosocial and environmental barriers to PrEP adherence. E-VOLUTION, an evidence-supported text-messaging strategy from the HIV care context, may reduce barriers to PrEP adherence if adapted for PrEP users. This study aimed to map barriers and facilitators to PrEP adherence using the four levels of the exploration phase of the Dynamic Adaptation Process (DAP) framework (system, organization, provider, and client).

Methods: Two, two-hour virtual participatory system dynamics workshops (group model building or GMB) were held with 15 PrEP providers and prevention staff across 4 regions of Alabama and Mississippi. A facilitator guided stakeholders through the Variable Elicitation script, creating a prioritized list of variables that increase or decrease PrEP adherence. Next, participants nominated causal links between variables while a modeler documented the emerging causal loop diagram (CLD) using the Zoom share screen function. The process continued until participants agreed the CLD accurately represented the system. The CLDs were then synthesized into a single CLD.

Virtual semi-structured interviews were conducted with 28 current and former PrEP users. Interviews were recorded, transcribed, and deductively coded based on barriers and facilitators to PrEP adherence. Codes and themes were established. Causal links in the text segments were identified and added to the CLD.

Results: Results depicted a system with four stocks (representing accumulations in the system that serve as catalysts for decisions), which mirrored the four, stacked levels in the DAP: system capacity (e.g. insurance and stigma), organization capacity (e.g. facility, health education, communication practices), provider capacity (e.g. knowledge and respect), and client capacity for PrEP adherence (factors discussed below). Each stock increases (or weakens) the capacity in the stocks below it through reinforcing feedback loops (loops that reinforce system behavior acting as virtuous or vicious cycles). Top-down and bottom-up feedback loops were present.

Reinforcing loop example one: This top-down loop demonstrates that as organizational capacity increases, organizational support for providers increases, provider capacity increases, which in turn strengthens the capacity of the organization. Further, an increase in provider capacity increases providers’ ability to support clients. It’s important to note that the loop is described here as operating virtuously. If organizational capacity declines, the rest of the system also weakens.

Reinforcing loop example two: A bottom-up reinforcing loop builds on the series of links in the example above. As providers’ ability to support clients increases, clients’ capacity for PrEP adherence increases. As adherence improves, providers learn what works and provider capacity increases. As provider capacity increases, organizational capacity increases. Further, as organizational capacity increases, reinvestment becomes more likely.

Client environmental and psychosocial loops: Several feedback loops related to client characteristics and capacity for PrEP adherence emerged. These loops included interactions involving mental health, stigma, social support, health literacy, and side effects and with the above stocks.

Conclusions: This study highlighted the value of identifying interactions and feedback between the exploration phase levels of the DAP. The detailed CLD provided insights about how to adapt E-VOLUTION to benefit clients and strengthen the capacity of the system.