How substance use, health insurance, and social determinants of health affect the HIV prevention continuum in Los Angeles, CA: Focus on Pre-Exposure Prophylaxis (PrEP) and Treatment as Prevention

BACKGROUND: Recent advances in biomedical HIV prevention – including pre-exposure prophylaxis (PrEP) and treatment as prevention (TAsP) – are key to ending the HIV epidemic. The analysis examined how social factors that are strongly related to HIV incidence and treatment outcomes (e.g., substance use, access to healthcare, age, race/ethnicity, gender, and geographic location) may affect the HIV prevention continuum. METHODS: Chapters 2 and 3 use data collected as part of clinical care at the Los Angeles LGBT Center. In Chapter 2, a cross-sectional study of HIV-negative men who have sex with men (MSM) and transgender people who have sex with men (TGSM) who visited the Center between August 2015 and April 2017 examined how sexual history, substance use, and demographic factors were associated with initiating PrEP. In Chapter 3, records-based longitudinal study of patients prescribed PrEP at the Center evaluated discontinuation, HIV incidence, and loss to follow-up. Chapter 4 uses data from the mStudy to analyze the relationship between methamphetamine use (urine drug screen and self-reported frequency) patterns and viremia among HIV positive MSM of color.RESULTS: Use of sex drugs, but not alcohol use, was associated with PrEP initiation among MSM and TGSM. Key demographic risks were associated with lower odds of PrEP initiation (Black or Latino race/ethnicity, younger age). About half of patients who started PrEP at the Center discontinued or were lost to follow-up. HIV incidence among those who discontinued was 1.4%, compared to 0.3% among those who were actively attending follow-up appointments. Persistence was highest for those receiving PrEP through a low-cost program, and lowest for younger people. Longitudinal patterns of frequent and/or recent methamphetamine use were associated with a detectable pattern of viremia. CONCLUSION: Because younger people had lower PrEP initiation and more discontinuation compared to older people, strategies to support youth are key to PrEP’s success for HIV prevention. The findings that methamphetamine was an obstacle to secondary HIV prevention but not necessarily to PrEP use highlight how facilitating PrEP use among people who use methamphetamine and other substances may be key to HIV prevention