Statement of the Problem: Men who have sex with men (MSM) make up only 2% of the population in the United States, but represent 60% of all HIV infections each year. Pre-exposure prophylaxis (PrEP), a once daily medication to prevent HIV infection, has emerged as a prevention tool for populations most heavily affected by HIV. However, the criteria for PrEP have only been broadly defined and lead many individuals and their medical providers to question if PrEP use is appropriate, given individual risk profile and potential drug side effects. The primary goal of this dissertation is to use risk assessment and HIV testing data to create an HIV risk score for HIV-negative MSM. The secondary goal is to use this HIV risk score to create more targeted criteria for PrEP use and subsequently inform individualized PrEP candidacy.
Methods: Behavioral risk assessment and HIV testing data were collected at the Los Angeles LGBT Center from January 2009 to June 2014. Individuals were included in the analysis if they were MSM, had an HIV-negative test result at baseline, and returned for at least one follow-up HIV testing visit (n = 9,981). Bivariate and Multivariate Cox Proportional Hazards Models were used to determine the biological, behavioral, and substance use variables significant in HIV contraction over the 5.5 year follow-up period.
Summary of Findings: Self-reported history of gonorrhea (p = 0.03), chlamydia (p < 0.0001), and syphilis (p = 0.01); having receptive anal sex (p < 0.0001), race/ethnicity of partners (p = 0.005), and number of sexual partners in the last three months (p = 0.0003); methamphetamine (p = 0.0008), and nitrate use (p = 0.002) were all significant predictors of HIV infection during follow-up. Age of partners, intimate partner violence, and ecstasy use were not significant. Following risk score creation, approximately 45% of all individuals were above a chosen risk score, which consisted of 76% of all HIV-positives. The use of this targeted strategy is beneficial in that it more accurately outlines PrEP candidacy criteria, subsequently allowing individuals and their medical providers to make a more informed decision before use.