A study of black HIV-negative men who have sex with men (MSM) given Truvada (tenofovir/emtricitabine) as pre-exposure prophylaxis (PrEP) has explored which factors are associated with higher levels of adherence to the daily drug regimen. An adherence analysis from the HPTN 073 study of 226 black MSM in three U.S. cities was presented at the 21st International AIDS Conference in Durban, South Africa (AIDS 2016).

Findings from the study were previously presented at the 2016 Conference on Retroviruses and Opportunistic Infections (CROI) in Boston. The study found that among the 178 men who agreed to take PrEP, five became HIV-positive, for an infection rate of 2.9 percent per year. This compared with an infection rate of 7.7 percent per year among the men who did not agree to take PrEP.

For this new analysis, the researchers relied on self-reports of adherence to the daily Truvada regimen. Between 62 and 71 percent of the participants reported high adherence (at least 90 percent of doses) at each of the study visits, which were conducted every 13 weeks. Between 13 and 19 percent of the partcipants reported taking the daily tablets less than half the time at the study visits conducted between week 13 and 52.

After adjusting the data for various factors, the researchers found that participants who were age 25 or older were 46 percent more likely to report taking at least 90 percent of their doses compared with younger participants; those with a two-year advance degree or higher were 59 percent more likely to adhere well compared with those with less education; those who reported taking multiple medications that were not prescribed to them were 51 percent less likely to adhere well compared with those who did not engage in “poly drug use”; and those with a primary partner were 75 percent more likely to adhere well compared with those who did not have one.

Considering those who reported taking less than half their Truvada doses, those who reported poly drug use were 3.3 times more likely to adhere poorly compared with those who did not report such drug use; and those with a primary partner were 58 percent less likely to report poor adherence compared with those who did not have one.

To read the conference abstract, click here.

Editor’s note: A previous version of this article mischaracterized the definition of polydrug use as the use of multiple recreational drugs rather than the use of multiple medications not prescribed for the study participants.