A new Web-based algorithm uses more refined criteria to better identify PrEP candidates at highest risk for HIV infection.
A newly formulated online personalized human immunodeficiency virus (HIV) risk score for initiation of pre-exposure prophylaxis (PrEP) is more specific than the current guidelines by the Centers for Disease Control and Prevention, according to a new study.
PrEP has emerged as a HIV prevention tool for those at highest risk for HIV infection. But current CDC guidelines for identifying PrEP candidates may not be specific enough to identify gay, bisexual, and other men who have sex with men (MSM) at the highest risk for HIV infection, state researchers led by Matthew Beymer, a post-doctoral scholar in the department of medicine, division of infectious diseases, at the David Geffen School of Medicine at UCLA.
The researchers published their results in the January 2017 Sexually Transmitted Diseases.
“We created an HIV risk score for HIV-negative MSM to develop a more targeted criterion for assessing PrEP candidacy,” they stated, adding that the PrEP Calculator is the first of its kind to be based on real-world data.
The researchers analyzed behavioral risk assessment and HIV testing data for 9,481 HIV-negative MSM attending the Los Angeles LGBT Center between January 2009 and June 2014, which serves approximately 13,000 individual clients annually.
They created an HIV risk score, and compared the model to current CDC guidelines. Unlike the CDC guidelines, they asked important questions about a number of factors that could put someone at higher risk for becoming infected, including substance use, number of sex partners, age and race or ethnicity, and other partner-level factors.
The results show that approximately 51% of MSM were above a cut point that the researchers chose as an illustrative risk score to qualify for PrEP, identifying 75% of all seroconverting MSM. “Our model demonstrated a better overall fit when compared with the CDC guidelines in addition to identifying a greater proportion of HIV infections,” they stated.
In conclusion, the researchers suggested that current CDC PrEP guidelines should be expanded to incorporate substance use, partner-level, and other variables that have been shown to contribute to HIV acquisition. “Deployment of such personalized algorithms may better hone PrEP criteria and allow providers and their patients to make a more informed decision prior to PrEP use,” they stated.
The researchers plan to assess whether MSM find it useful in determining if they should start taking PrEP. Even as late as September 2016, 20% of the Los Angeles LGBT Center’s clients were unsure if PrEP was an appropriate choice, Beymer said.
“The findings from this study will allow MSM to determine their overall risk for HIV based on their own data and previous data collected at the Los Angeles LGBT Center,” Beymer said. “Ultimately, this HIV risk score can be used by the client to determine if PrEP is right for them.”
Beymer noted that the calculator has limitations in that it may not be appropriate for heterosexual and trans individuals, injection drug users, or people living outside of Los Angeles. In addition, it does not consider situations in which HIV-negative men are in long-term relationships with HIV-positive men.