Breaking Inertia: Movement Along the PrEP Cascade in a Longitudinal US National Cohort of Sexual Minority Individuals at Risk for HIV

Background: The pre-exposure prophylaxis (PrEP) cascade outlines sequential steps to maximize PrEP's impact and highlights potential intervention targets to improve PrEP implementation. We evaluate the PrEP cascade in the Together 5000 study (T5K). Methods: T5K is an internet-based, US national cohort study of PrEP-eligible men and trans persons who have sex with men who were not taking PrEP at enrollment. Using longitudinal data from baseline (2017-2018) and year 1 follow-up (2018-2019, n = 4229), we evaluated 5 steps of the PrEP cascade-PrEP contemplation: believes they are a good candidate for PrEP; PrEParation: plans to initiate PrEP; PrEP action: speaks to a provider about PrEP; PrEP initiation: receives a prescription for PrEP; and PrEP maintenance: continues to take PrEP. We compared the cascade across geographic region and identified factors associated with gaps in the cascade. Results: After 1 year, 1092 (26%) participants had initiated PrEP, 709 (17%) were still using PrEP, and 177 (4%) were no longer clinically indicated for PrEP. Participants in the South and Midwest were less likely to speak to a provider about PrEP or initiate PrEP. Baseline characteristics associated with lower odds of PrEP initiation at year 1 include: not having a college degree; earning <$20,000/year; not having health insurance; having very low food security; and not having a primary care doctor. Conclusions: Lack of health care access is a major barrier to PrEP implementation and may exacerbate disparities in PrEP uptake across geographic regions.