Background
Despite ongoing efforts to address racial disparities in HIV incidence, the Black/African American and Hispanic/Latino populations continue to be disproportionately affected by new HIV diagnoses. The current study aimed to explore the temporal trend of racial disparities in HIV incidence at the county level across the United States from 2008 to 2021, and to identify potential social determinants that contribute to these variations.
Methods
We used three measurements to quantify racial disparities in HIV incidence, including rate ratio, disparity index, and population-weighted disparity index. Temporal trends in these indices were analyzed using Joinpoint regression. Linear mixed-effects models were applied to explore the relationship between racial disparities in HIV new diagnosis rates and social vulnerability index (SVI), as well as other social determinants variables.
Results
From 2008 to 2021, the Black-to-White rate ratio displayed an overall decreasing trend (Average Annual Percent Change [AAPC] = -1.41, P<0.05), and two turning points were identified in 2012 and 2015. This ratio declined from 2008 to 2012, increased from 2012 to 2015, and resumed declining after 2015. The Hispanic-to-White rate ratio also showed an overall decreasing trend (AAPC=-1.60, P<0.05), with 2010 being the turning point. However, the weighted Index of Disparity showed a significant upward trend (AAPC=1.32, P<0.05). Regarding social determinants, counties with higher social vulnerability had lower degrees of racial disparities in HIV incidence, indicated by lower values of Black-to-White rate ratio (β=-1.49, P<0.05) and population-weighted disparity index (β=-39.50, P<0.05). Other county-level characteristics, such as per capita income, population aged 25 years and Persons (age 25+) without a high school diploma, and the proportion of the population not proficient in English, were also associated with higher racial disparities in HIV incidence (P values < 0.05).
Conclusions
From 2008 to 2021, racial disparities in HIV diagnosis rates shifted significantly in the U.S. The Black-to-White rate ratio and the Hispanic-to-White ratio decreased overall while the population-weighted disparity index increased. Social factors, particularly the Social Vulnerability Index (SVI), were strongly associated with these disparities, highlighting the need for targeted interventions addressing social determinants to reduce HIV racial disparities.
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