A support intervention based on cognitive behavioural therapy (CBT) significantly improved adherence among people enrolled in an HIV pre-exposure prophylaxis (PrEP) study, investigators report in the August 15 edition of the Journal of Acquired Immune Deficiency Syndromes. Participants were enrolled in the Partners PrEP study and all had an HIV-positive partner.
They became eligible for the adherence support counselling if an unannounced pill count showed they had taken fewer than 80% of doses in the preceding month. Participation in the intervention increased average adherence to PrEP by a significant 8% one month later. The study was conducted in Uganda.
Treatment with PrEP can significantly reduce the risk of infection with HIV for HIV-negative individuals. The treatment has the greatest efficacy in people with high levels of adherence.
Little is known about the best way to support adherence among people taking PrEP.
A sub-analysis of the Partners PrEP study therefore explored the effectiveness of an adherence supportive intervention using CBT techniques. The intervention was initially developed to support people taking antiretroviral therapy for the treatment of HIV infection.
The Partners PrEP study involved serodiscordant couples (couples in which one partner has HIV and the other does not). PrEP consisted of either tenofovir or emtricitabine and tenofovir (the drugs combined in Truvada). These treatments reduced the risk of infection with HIV by 67% and 75%, respectively. However, efficacy reached 86% and 90%, respectively, for people with detectable plasma tenofovir.
“PrEP, given sufficient adherence, is a promising biomedical intervention strategy for HIV-negative people to prevent infection,” comment the authors. “It is likely that at least some subset of PrEP users will require adherence support.”
A total of 1147 people were enrolled in the sub-analysis. A pill count showed that 168 individuals (15%) had adherence below 80% and these participants were eligible for the adherence intervention.
Factors associated with eligibility for counselling were male sex (p < 0.001), younger age (p < 0.001), higher monthly income (p = 0.02), employment as a labourer or in trade/sales (p = 0.001) and shorter duration of serodiscordant relationship (p < 0.001).
The adherence support sessions explored beliefs about PrEP, stigma associated with the treatment and barriers to adherence.
Participants received a median of ten adherence counselling sessions. The most commonly reported barriers to adherence were travel (identified by 50% of participants) and simple forgetfulness (identified by 45% of participants).
Mean adherence in the month before the counselling was 76%. Assessment using MEMS electronic monitoring showed this increased significantly to 84% in the month after the first counselling session (p < 0.001).
Adherence then declined from this peak, but after twelve months of follow-up it was still higher than at baseline.
“A PrEP adherence intervention…was associated with a temporal improvement in electronically monitored adherence to daily PrEP pill taking,” write the authors. “Adapting an evidence-based behavioural ART treatment intervention to support PrEP adherence in a trial of HIV-sero-discordant couples was also feasible.”
They conclude, “biomedical agents for the prevention of HIV should be used in conjunction with behavioural interventions to maximize their biological effectiveness.”
Psaros C et al. An intervention to support prexposure prophylaxis adherence in HIV-serodiscordant couples in Uganda. J Acquir Immune Defic Syndr, 66: 522-29, 2014.