POP-UP Mobile: A Mixed Methods Study of Mobile Outreach for People with HIV with Housing Instability Who Are Out of Care from a Low-Barrier Clinical Program in San Francisco.

Homelessness adversely impacts continuity of care for people with HIV (PWH). The POP-UP program is a low-barrier drop-in care model embedded within an HIV clinic in San Francisco and is designed to serve PWH experiencing homelessness. We conducted a pilot study of mobile outreach for PWH in POP-UP who remain out-of-care despite the drop-in program. We conducted a mixed-methods study to evaluate the effectiveness of mobile outreach through a retrospective cohort of PWH eligible for this outreach and semistructured interviews. Patients with POP-UP were eligible for outreach if they had (1) HIV viral load ≥200 copies/mL and no visit in ≥30 days, (2) no clinic visit in ≥180 days, or (3) urgent re-engagement need identified by the clinic team. We report the proportion of patients re-engaging in clinic-based care within 30 days and thematic findings from semistructured interviews with patients who experienced mobile outreach. Of 74 patients eligible for outreach, 55 were outreached, 48 located, and 30 returned to clinic within 30 days. Most were currently housed in a single-room occupancy hotel (39%) or permanent supportive housing (25%), 87% had a substance use disorder, and 51% had a mental health diagnosis. Qualitative findings highlighted the value of mobile outreach in terms of interpersonal relationships with the clinical team and the perception that outreach was a helpful nudge to return to clinic. Among PWH with housing instability who are out-of-care despite access to drop-in clinic-based services, mobile outreach was acceptable and promising for locating patients and facilitating care re-engagement.