PrEP In People Who Inject Drugs: Factors Associated with Patient Uptake And Adherence

The Bangkok Tenofovir Study demonstrated that pre-exposure prophylaxis (PrEP) with once-daily tenofovir decreased HIV seroconversion among people who inject drugs by 49%. After study completion, participants could continue once-daily directly observed administration of tenofovir for PrEP in a one-year open-label extension phase to identify participant factors associated with the decision to take daily tenofovir as PrEP, the decision to return for ≥1 PrEP follow-up visit, and >90% adherence to PrEP. Of the 2306 surviving study participants, 1315 were eligible to continue; 798 (61%) chose to start open-label PrEP and were followed up for a median of 335 days, and 339 (42%) completed 12 months of follow-up. The 573 participants who returned for ≥1 visit contributed 474 person-years of follow-up.

• Participants who were ≥30 years of age (odds ratio [OR], 1.8), injected heroin (OR, 1.5), or had been incarcerated (OR, 1.7) during the randomized trial were more likely to choose ongoing PrEP than their counterparts.
• Participants who reported injecting heroin (OR, 3.0) or being in prison during the 3 months before open-label enrollment (OR, 2.3) were more likely to return for ≥1 open-label follow-up visit than their counterparts.
• Only 25% of participants who returned for ≥1 follow-up visit were >90% adherent to the medication. Participants who injected midazolam (OR, 2.2) or who were in prison during follow-up (OR, 4.7) were more likely to be >90% adherent than their counterparts. One participant tested positive for HIV.

Comments: This extension study demonstrates that patients with perceived high risk of HIV seroconversion (i.e., those with ongoing injection use and those who may have a high relapse potential after release from incarceration) are interested in choosing to take PrEP for HIV prevention. What remains to be determined is how to enhance adherence and a deeper understanding of cost-implications for this population.

Jeanette M. Tetrault, MD

Reference: Martin M, Vanichseni S, Suntharasamai P, et al. Factors associated with the uptake of and adherence to HIV pre-exposure prophylaxis in people who have injected drugs: an observational, open-label extension of the Bangkok Tenofovir Study. Lancet HIV. 2017;4(2):e59–e66.