Mapping Pathways is a multi-national project to develop and nurture a research-driven, community-led global understanding of the emerging evidence base around the adoption of antiretroviral-based prevention strategies to end the HIV/AIDS epidemic. The evidence base is more than results from clinical trials - it must include stakeholder and community perspectives as well.

23 April 2012

Adherence – the key to success?

Original content from the Mapping Pathways blog team

A recent Mapping Pathways post talked about how the Partners PrEP study helped some couples work through their relationship problems – these couples saw the trial as a way to save their strained marriages. A key finding from the trial was the high level of adherence observed amongst the participants. The HIV-negative partner would remind the HIV-positive partner to take medication on time, replenish pill supplies, and keep follow-up appointments with counselors.

Adherence was also a key issue that came up at the Conference on Retroviruses and Opportunistic Infections (CROI) held recently in Seattle, Washington. Adherence is critical to interpreting the results in any trial, since a study pill, if not taken as directed, can make a highly effective pill appear ineffective.

A case in point is the FEM-PrEP study that involved 2,056 HIV-negative women in South Africa, Kenya and Tanzania who were randomly assigned to take either a daily Truvada pill or a placebo pill. However, the trial was stopped in April 2011 due to “futility” when an interim analysis discovered both trials arms having near-identical HIV infection rates. There were 33 HIV infections in women taking Truvada and 35 in women taking placebo.

While the participants in the study stated that they took their pills 95% of the time, drug levels found in the blood of women assigned to the Truvada study wing indicated that less than 50% of the women had actually taken the drug in the last 12 days.

In contrast, the Partners PrEP study, which enrolled 4,758 seriodiscordant (one partner HIV-negative and the other HIV-positive) couples in Kenya and Uganda, indicated adherence to medication at almost 97%. 

Why was there such a drastic difference in the levels of adherence in the two trials? Investigators suggested that the differences in population between the two studies could be one reason. The Partners PrEP study involved couples who defined themselves as being in long-term, stable relationships, which was one of the pre-requisites for lasting through the two-year-long trial.

On the other hand, the women recruited for the FEM-PrEP study were much younger and there was no such requirement of being in a stable relationship. Initial qualitative surveys indicated these women did not believe themselves to be at a high risk of HIV, despite high incidence in the community around them. 

In short, the Partners PrEP study had in-built adherence motivators, in the form of committed partners, many of who participated in the whole process and actively helped their companions adhere to pill intake.

Could similar intrinsic motivators have improved the rate of adherence to medication in the FEM-PrEP study? And could similar subtle motivators be incorporated in other studies to improve the rates of adherence?

“Adherence is the word on everyone’s lips and minds these days – at CROI, at M2012, among trial designers, program implementers and advocates,” says Jim Pickett, Director of Prevention Advocacy and Gay Men's Health at the AIDS Foundation of Chicago and a Mapping Pathways member.

Stay tuned to the Mapping Pathways blog for more interesting posts on the important issue of adherence.

[Content that is linked from other sources is for informational purposes and should not construe a Mapping Pathways position.]

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