Background
The scale up of Pre-exposure Prophylaxis (PrEP) has been associated with reduced community HIV transmission. The population-level impact of PrEP coverage, particularly the extent to which PrEP needs were met, on HIV incidence, is still not well understood. This study aims to explore the longitudinal associations between PrEP-to-Need Ratio (PNR) and changes of HIV incidence rates across all the counties in the United States.
Methods
Several publicly available data sources were linked by county level Federal Information Processing Standards (FIPS) code and used for analysis. The PNR, which was retrieved from AIDSVu, was calculated as the ratio of PrEP prescriptions (numerator) to new HIV diagnoses (denominator) in each county per year between 2012 and 2021. Our outcome of interest was change in HIV incidence between two consecutive years. Correlation analyses were performed to assess the relationship of percent change of PNR with change of HIV incidence overall and HIV incidence racial disparities between 2012 and 2021. Linear mixed effects (LMM) models were performed to use PNR value in one calendar year to predict the HIV incidence change in the subsequent year in both “Ending the HIV epidemic initiative” (EHE) areas and across the US, adjusting social determinants of health.
Results
The correlation analysis from the 48 EHE counties revealed that percent change of PNR between 2012 and 2021 was negatively associated with the overall HIV incidence change (β=-0.34, P=0.0165) and positively associated with the change of racial disparities of HIV incidence between Hispanic and White populations (β=0.31, P=0.0304), but not associated with the change of racial disparities of HIV incidence between White and Black populations (β=0.23, P=0.1124). LMM models showed that PNR has a significant negative impact on changes in HIV incidence rates in all areas implementing the EHE initiative (β=-0.1297, P=0.0018) and across the entire United States (β=-0.0876, P<0.0001).
Conclusions
The results of this study highlighted the protective effect of PrEP use in reducing HIV incidence but also alarmed us about the wider HIV incidence disparity between Hispanic and White populations. To further promote the widespread use of PrEP and achieve health equity, future research should focus on developing and implementing more targeted intervention strategies.