The SUSTAIN 2 Study - SUStained HIV Treatment for Adherence After Interruption in Care

Differentiated Service Delivery (DSD) models have been shown to provide equivalent or better retention in healthcare and viral (VL) suppression for people with HIV than conventional care models. However, to date, DSD models have been offered only to people with HIV (PWH) considered 'stable' (i.e., retained in care and virally suppressed). Thus, those at high risk of poor outcomes are ineligible for DSD models. In response, the investigators will work with the City of Cape Town to provide the data needed to impact policy guidelines. The investigators designed SUSTAIN2: SUStained HIV Treatment Adherence After INterruption, which will test a scalable, evidence-based DSD model (SUSTAIN-DSD) to address individual, social, and structural barriers to long-term engagement and to increase VL suppression among PWH with an ART treatment interruption or unsuppressed VL (PWH-Gaps).

SUSTAIN-DSD is a six-month adherence club model of care that offers flexible services with multi-month dispensing of medication (de-linked from clinic processes) and support from lay counselors and peers, which has been proven to help PWH to sustain retention and viral suppression in the Western Cape. The study will implement a Hybrid Type 1 randomized controlled trial (RCT) to evaluate the effectiveness of SUSTAIN-DSD on viral suppression among PWH-Gaps at 24 months post-enrollment, as compared to an enhanced standard-of-care (an optimized guidelines-based approach). The investigators will recruit 300 participants from the parent study and clinics (SUSTAIN, R01MH125703, MPI: Orrell/Sabin; UCT Ethics Reference 568/2021), through which the investigators have identified persistent engagement gaps in approximately 45% of the participants, despite adherence counseling, to test this model of care. The investigators will then assess the mechanisms of intervention impact using mixed methods, guided by the Capability, Opportunity, and Motivation model of Behavior (COM-B), and determine implementation outcomes using Proctor's model.

Ultimately, the investigators' goal is to ensure that PWH are able to achieve and maintain virologic suppression through provision of an effective and efficient model of care, which can be used in South Africa's efforts to reach the 2030 goals.

The investigators' central hypothesis is that PWH-Gaps receiving SUSTAIN-DSD will have higher rates of viral suppression than those who receive enhanced routine care. The investigators will use a Hybrid Type 1 RCT design to answer the study questions.

Inclusion criteria

• Adults (≥18 years or age)
• Living with HIV
• On a dolutegravir-based first-line ART regimen
• Evidence of a care gap (>28 days late for appointment) or having a raised viral load (≥50 copies/ml) in the preceding year, either from SUSTAIN study data or from clinic records.
• Able to provide full informed consent.
• Willingness to comply with study procedures, including providing regular update of contact details or locator information.

A purposively selected subset of 30 enrolled participants will be invited for a semi-structured, in-depth interview at (or within 2 months after) the month 24 visit (for experience and perceptions; aim 2); and 20 different participants will be invited to participate in in-depth interviews to determine acceptability and feasibility (aim 3) within the same time frame.

Exclusion criteria

at Enrollment:

• Clinical conditions as assessed by the ART clinicians as requiring clinic-based follow-up e.g. tuberculosis or epilepsy.
• Pregnant at enrollment and requiring care in the antenatal clinic system.
• Sustained retention in care (no gaps of >28days) and viral suppression in the preceding year.
• Plans to leave Cape Town permanently within the next 24 months.