OBJECTIVES: Pre-exposure Prophylaxis (PrEP) can greatly help to prevent Human Immunodeficiency Virus (HIV) infections. However, the uptake of PrEP is low among at-risk individuals due to several factors, including the Social Determinants of Health (SDOH). This study assessed county-level SDOH associated with county-level PrEP use to need ratio (PnR) in the United States (US).

METHODS: A cross-sectional study was conducted using the AIDSVu dataset merged with County Health Rankings (CHR) dataset for the year 2021. AIDSVu includes data from state and local health departments. The outcome variable was county-level PnR (i.e., the ratio of PrEP users to new HIV cases in a county with a higher PnR indicating better PrEP utilization in the county). Descriptive statistics were used to examine the county-level PnR across thirty-four SDOH variables, and regression analyses were conducted to assess the association of SDOH-related factors with county-level PnR.

RESULTS: The study included 691 counties with valid PnR; the mean county-level PnR was 8.9 [standard error, (SE)=7.5]. The regression model found that the percentage of people with poor/fair health (b_z=0.501, p=0.003), number of mental health providers (b_z=0.383, p<0.01), and number of social associations (b_z=0.563, p<0.01) were associated with higher PnR. In contrast, the percentage of the following: births with low birthweight (b_z=-0.146, p=0.024), smokers (b_z=-0.251, p=0.004), chlamydia cases (b_z=-0.448, p<0.01), physically inactive individuals (b_z=-0.243, p=0.001), and uninsured individuals (b_z=-0.131, p=0.009) were associated with lower PnR. Lastly, the poor physical environment of a county indicated by days with poor air quality (b_z=-0.067, p=0.040) and a percentage of people having severe housing problems (b_z=-0.155, p=0.006) were associated with lower PnR.

CONCLUSIONS: Understanding the variability of county-level PrEP across various SDOH can help to focus on county-level priorities for improving PrEP- uptake in the US.