Barriers and Facilitators to PrEP Adherence among Transgender and Non-binary Individuals: A Mixed-Methods Analysis of Psychosocial Factors and Health Belief Model Constructs.

Despite known benefits of Motivational Interviewing (MI) for medication adherence, its effectiveness in supporting pre-exposure prophylaxis (PrEP) adherence among transgender and nonbinary (TGNB) populations remains underexplored. This study applies mixed-methods analysis to understand PrEP adherence among TGNB individuals who received a daily individualized text-message intervention and phone-based MI for non-adherence to PrEP. Individuals who did not respond to three consecutive messages were identified as potential MI recipients. We had three objectives: (1) examine psychosocial differences between participants who needed MI (MI Indicated group; n = 81) versus those who did not (MI Not Indicated group; n = 48), (2) assess whether Health Belief Model (HBM) constructs were associated with PrEP adherence, and (3) identify adherence barriers and facilitators. This secondary analysis builds on primary intervention outcomes published in Morris et al. (J Acquire Immune Defic Syndr 91:453-459, 2022). We conducted multivariable linear regression on psychosocial measures and PrEP adherence, and inductive qualitative analysis on a subset of participants who completed at least one MI session (n = 60). Results were deductively mapped onto HBM constructs. Significant differences emerged between MI groups in HBM constructs, with the MI Indicated group reporting higher perceived HIV risk, stress, depressive symptoms, and poorer coping and self-efficacy. Findings highlight the need for personalized interventions to support PrEP adherence, mental health, and HIV risk perception among TGNB individuals. Future adherence interventions may benefit from assessing and addressing HBM constructs. To support the Ending the HIV Epidemic initiative, it is critical to enhance access to facilitators and mitigate barriers to PrEP adherence for this population.