PrEP, Prevention, and Place: Examining the Effect of Geographic Accessibility on the Use of HIV Pre-Exposure Prophylaxis Open Access

Sharpe, Danielle (Fall 2021)

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Pre-exposure prophylaxis (PrEP) is an antiretroviral medication that is effective for preventing HIV transmission in HIV-negative persons; however, PrEP uptake is low in the U.S. Suboptimal geographic proximity to PrEP services is recognized as a contributor to such low uptake. This dissertation examined the geographic accessibility of PrEP-providing clinics in the U.S. over time and investigated the associations between area-level geographic accessibility of PrEP and individual-level use of PrEP across urbanicity levels. First, we examined the spatiotemporal distribution of PrEP accessibility from 2016-2020 and characterized factors contributing to this distribution. We found a decrease in PrEP deserts by 52.8% and an increase in PrEP oases by 33.5% between 2016-2020. Of 72,339 census tracts, 12,487 (17.3%) were persistent PrEP deserts, 753 (1.0%) were new PrEP deserts, 15,568 (21.5%) were new PrEP oases, and 43,506 (60.1%) were persistent PrEP oases between 2016-2020. Persistent PrEP oases were more likely to be of higher socioeconomic status, racially/ethnically diverse, located in urban areas, and located in the Northeast compared to other spatiotemporal PrEP accessibility types. Next, we investigated the association between geographic accessibility of PrEP-providing clinics and PrEP use among men who have sex with men (MSM) residing in nonurban areas in the U.S. We found that suburban MSM residing in PrEP deserts were less likely to use PrEP in the past year than suburban MSM not residing in PrEP deserts. Other nonurban MSM residing in PrEP deserts were also less likely to use PrEP in the past year than other nonurban MSM not residing in PrEP deserts but at a smaller magnitude than suburban MSM. Lastly, we investigated the association between transportation modes used to access healthcare services and persistent PrEP use among MSM in urban areas. We found that urban MSM using public transportation had lower odds of PrEP persistence than urban MSM using private transportation. We found no significant associations between PrEP persistence and using multiple transportation modes or active transportation modes. The findings of this dissertation will inform the spatial allocation of PrEP-providing clinics and tailored transportation-related interventions to improve PrEP use among MSM populations in the U.S. across urbanicity levels.

Table of Contents

Chapter 1. Background and Significance   1

Chapter 2. The spatiotemporal distribution of pre-exposure prophylaxis accessibility in the United States, 2016-2020   16

Chapter 3. Association between the geographic accessibility of pre-exposure prophylaxis and use of pre-exposure prophylaxis among men who have sex with men in nonurban areas   36

Chapter 4. Effects of mode of transportation on pre-exposure prophylaxis persistence among urban men who have sex with men during the COVID-19 pandemic   60

Chapter 5. Conclusions and Future Directions   74

References   80

Appendix   98

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