Despite its efficacy, pre-exposure prophylaxis (PrEP) for HIV has a low uptake, with many disparities remaining. This study aimed to assess the impact of Medicaid expansion and social determinants of health (SDOH) on PrEP prevalence and PrEP-to-need ratio (PnR) using county-level data from 2012 to 2022. Differences-in-differences regressions indicated that Medicaid expansion is associated with increased PnR but not PrEP prevalence. Linear regressions were conducted to evaluate the impact of county-level SDOH on PrEP outcomes. Rurality was associated with lower PnR and PrEP prevalence. Racial disparities were present, with areas with greater concentrations of non-Hispanic Black populations having lower PrEP prevalence and PnR. Greater concentrations of Hispanic populations were associated with lower PnR. Income inequality, socioeconomic status vulnerability, and primary care physician concentration were all associated with higher PnR. Medicaid expansion supports increasing PrEP use in the areas of greatest need. Efforts should be made to improve PrEP access, particularly in areas with high SDOH vulnerabilities.
Keywords: HIV; Medicaid expansion; PrEP; SDOH; disparities; pre-exposure prophylaxis.