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
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
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
support sessions explored beliefs about PrEP, stigma associated with the
treatment and barriers to adherence.
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).
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.”
“biomedical agents for the prevention of HIV should be used in conjunction with
behavioural interventions to maximize their biological effectiveness.”