Geospatial Accessibility Factors Influencing HIV Care Continuum Outcomes in South Carolina

Ending the HIV epidemic in the U.S. requires access to comprehensive care. Traditional measures of service access have focused on distance and time. This study used the enhanced two-step floating catchment area (E2SFCA) method to measure geospatial accessibility and its association with HIV care continuum outcomes. Data from South Carolina's 2020 enhanced HIV/AIDS reporting system (eHARS) were used to calculate aggregated county-level percentage linkage to care (LTC), retention in care (RIC), and viral suppression (VS) among adult people living with HIV (PLWH). E2SFCA was used to measure geospatial accessibility, using the 60-min index as the threshold. County-level mean percentage of dependent variables and covariates were calculated. A linear regression model (LRM) was used to evaluate the association between accessibility index and LTC, RIC, and VS after adjusting for covariates. Accessibility index ranged from 17.9 to 198 across the 46 counties (mean = 67.5, SD = 36.5). Counties with better accessibility were more likely to have a higher percentage of LTC (β = 5.07, 95% CI = 0.83, 9.31) but a lower percentage of VS (β = -2.85, 95% CI= -4.60, -1.10). The negative association between accessibility index and VS was moderated by the percentage of household without vehicle ownership (β = 2.00, 95% CI = 0.02, 4.00). No association was found between the accessibility index and RIC. Counties with lower uninsured rates (β= -3.11, 95% CI= -5.35, -0.87) had higher % LTC. Suboptimal geographic accessibility to HIV care is an important structural barrier in South Carolina. Targeted policies and interventions are needed to address this challenge.