A realist-informed evaluation of the implementation of complex HIV treatment support strategies for female sex workers living with HIV

Purpose: In South Africa, female sex workers (FSW) living with HIV have suboptimal treatment outcomes. The Siyaphambili trial tested two strategies to promote viral suppression. This paper identifies why and under what conditions the strategies were appropriate, feasible, implemented with fidelity, and ultimately effective for FSW living with HIV. Methods: Guided by the Consolidated Framework for Implementation Research, we conducted in-depth interviews with 36 Siyaphambili participants using maximum variation sampling and purposively selected 12 key informant implementors. We generated ‘Context + Mechanism = Outcome’ configurations using deductive coding and retroductive inference. Results: Overall, strategy appropriateness for FSW reflected how “the needs of innovation recipients” enhanced/challenged the “relative advantage” of the strategies. Feasibility of implementation resulted from the interaction of the “work infrastructure”, “available resources”, and access to “knowledge and resources,” which activated/dampened the “design” of the strategies. Fidelity of implementation relied on how “partnerships”, “relational connections” and “communication” influenced strategy “complexity” and “adaptability.” Strategy effectiveness depended on the influence of FSW “capability” on their “motivation and opportunity.” Conclusions: Understanding the conditions in which these strategies did or did not work aids in understanding the why this pragmatic trial failed to achieve anticipated results and informs potential success that can be taken forward to better optimize treatment outcomes for FSW.