County-Level New HIV Diagnoses, Social Determinants of Health, and Residential Segregation by U.S. Region 2013 to 2023: A Longitudinal Analysis

Health disparities persist along the HIV care continuum. As new HIV diagnoses are a key indicator of the HIV epidemic, we aimed to assess associations of the social determinants of health (SDOH; non-medical factors that are related to health outcomes) and residential segregation, as a proxy for systemic racism, with new HIV diagnosis rates across the major regions of the United States. Publicly available county-level data (i.e., 2013-2023) from an interactive visualization and mapping tool of the HIV epidemic (AIDSVu) and the American Community Survey (ACS) were merged using Federal Information Processing System (FIPS) codes and categorized into four U.S. regions. A Generalized Estimation Equation (GEE) model was run, within each region, to explore the associations between the SDOH, residential segregation, and new HIV diagnoses, over time. Overall, 3,051 counties (97.04%, n = 3,051/3,144) across the four major regions of the U.S. were included in the analysis (i.e., South = 1,398, North = 207, West = 408, Midwest = 1,038). By region, counties with a higher proportion of males aged 18-34 (South: IRR = 1.02, p < 0.001), males aged 35-54 (South: 1.06, West: 1.07, Midwest: 1.13, p < 0.001), Black populations (South: 1.38, North: 1.16, West: 2.78, p < 0.001; Midwest: 1.61, p < 0.01), and individuals experiencing poverty (West: 1.24, p < 0.01; Midwest: 1.78, p < 0.05), or without health insurance (South: 1.02, p < 0.001) were associated with higher rates of new HIV diagnoses. Dimensions of residential segregation (i.e., Gini Index, Delta Index, Spatial Proximity Index) were found to be, primarily, positively associated with new HIV diagnoses in all regions. Two interaction terms were found, Black x Delta (South: 0.91, p < 0.001; West: 0.89, North: 0.81, p < 0.05) and Poverty x Gini (Midwest: 0.62, p < 0.001). Overall, these findings demonstrate ongoing disparities in vulnerabilized populations and an increased likelihood of new HIV diagnoses within counties with higher residential segregation, leading to a call for structural interventions and policy that address systemic racism and subsequent, negative health outcomes.