Predicting PrEP Use Based on PrEP Indications Among MSM

There are MSM who are indicated for PrEP use that don’t use it, and vice versa, the study authors found.

HIV pre-exposure prophylaxis (PrEP) indications strongly predicted current PrEP use among men who have sex with men (MSM) in the United States, according to a paper published in the Journal of the International AIDS Society.

Investigators from Emory University in Atlanta identified 3508 HIV-negative MSM from a web-based network of participants between 2017 and 2019 in order to determine whether the association between PrEP indications and PrEP use differed by demography or geography. The study authors also wanted to estimate PrEP use among MSM and assess if their PrEP use aligned with their current indications for PrEP.

From the database, the investigators were able to measure PrEP usage and see if the respondents met indications for PrEP, which include self-reported behaviors such as the number of recent sexual partners, whether the partnership was with a main, casual, or one-time partner, the dates of the partnership, what sexual activities occurred, whether the participant and partner were using PrEP or antiretroviral therapy or condoms, and the responder and partner’s histories of STI diagnoses.

Then, the study authors matched South, Midwest, Northeast, West designations to participant-reported zip codes and race/ethnicity data, including non-Hispanic Black, non-Hispanic White, Hispanic, other race/ethnicity. Age groups were also considered: 15-17 years; 18-24; 25-34; 35-44; 45-54 and 55-65.

A majority of the responders who were eligible reported using PrEP (82 percent), the study authors determined. Of the 631 who reported using PrEP, more than half met indications for PrEP use but 40 percent did not. The study authors found that a third of PrEP-indicated MSM reported currently using PrEP.

Of the group who did not meet indications for PrEP, 10 percent were currently using PrEP, the authors learned.

Nearly a third of all the men who were eligible for PrEP (the larger group) had PrEP usage misaligned with their current indications, and a further 7 percent of PrEP-eligible MSM were currently using PrEP despite not meeting its indications, the study authors observed. Furthermore, the study authors wrote that nearly a quarter of PrEP eligible MSM were not using PrEP despite meeting indications for PrEP.

The lowest PrEP use was found in the South, and was greatest in the West. The study authors also found that PrEP use increased with age, with the lowest use in the youngest age groups (15-17 and 18-24-year-olds) and the highest use among 45-54-year-old MSM.

The study authors did not find a significant variation in current PrEP use by race/ethnicity, they said, but found the lowest use among Hispanic MSM. Despite not meeting indications for PrEP, usage was greatest among non-Hispanic White, Northeast, and 45-54-year-old MSM the study authors said.

“We found evidence of substantial misalignment between the US Public Health Service indications for PrEP and current PrEP use among PrEP-eligible MSM,” the study authors concluded. They also wrote that monitoring of PrEP uptake is needed in order to measure progress toward closing the gaps in PrEP coverage. Currently, PrEP uptake among MSM tracked with prior estimates and meeting PrEP indications was linked to current usage; however, there are populations who are indicated for PrEP that do not use it and those who use it while not meeting the indications, they wrote.

“The relative importance of behavioral indications and demographic differences in PrEP uptake highlight potential barriers to and gaps in implementing PrEP, both in the United States and globally, which will need to be addressed to meet PrEP's full potential to reduce new infections, particularly given efforts to both scale-up and address structural barriers to accessing PrEP in the United States.”