Background
Limited research evaluates the degree and tendency of racial disparities of viral suppression (VS) among people with HIV(PWH) across the Southern US. This study aims to examine the spatiotemporal trend and structural social determinants (e.g., socioeconomic and structural environment factors) of racial disparities in VS.
Methods
A statewide population-based retrospective cohort study was conducted using the South Carolina (SC) HIV registry system from 2013 to 2020. The county-level viral suppression percentage was defined as the percentage of PWH with a viral load < 200 copies/ mL at most recent test per county per year. Racial disparities in the county-level percentage of VS were measured by four indexes: Black to White Ratio (BWR), Index of Disparity (ID), Weighted Index of Disparity (Weighted ID), and Gini coefficient. Linear mixed-effect models were used to assess the association between different contextual factors and these indexes. Linear trend test was further employed to explore the temporal trend of the disparity indexes.
Results
VS rates across the 46 counties in SC increased from 75.01% in 2013 to 82.60% in 2020. However, an increasing trend of the changes of racial disparity in VS was observed, measured by ID and Weighted ID (P<0.01). In contrast, the results of BWR and Gini coefficient showed a decreased trend (P<0.01). When using ID as an outcome, counties with higher institutional health (β=1.2, P<0.05) were at a higher risk of racial disparities in VS. For Weighted ID, counties with worse socioeconomic status (β=-0.64, P<0.05) were at a higher risk of racial disparities in VS. For Gini coefficient, counties with more Ryan White HIV centers (β=-0.004, P<0.05) and higher disability rates (β=-0.005, P<0.05) had lower risk of racial disparities in VS. Comparing to Lowcountry region, counties in PEE DEE region existed lower risk of racial disparities in VS across multiple indices, including ID, Weighted ID, and Gini coefficient (β=-3.12, -0.88, and -0.01, respectively, P<0.05).
Conclusions
The choice of disparity measures may affect the interpretation of changes in health disparities. More comprehensive and standardized indicators are needed to provide a clear picture of racial disparity change. Nevertheless, structural factors such as higher institutional health and worse socioeconomic status may exacerbate the racial disparities, which underscores the importance of addressing these factors that contribute to poor HIV outcomes, particularly among marginalized populations.
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