Female participants in a failed study of Truvada (tenofovir/emtricitabine) as pre-exposure prophylaxis (PrEP) often lied about their pill use in order to remain in the study, aidsmap reports. The FEM-PrEP study of 2,120 women in sub-Saharan Africa was stopped early in 2011 because women in the Truvada arm were no less likely to contract HIV than those in the placebo group. Low adherence to PrEP turned out to have crippled the study.

Researchers from FEM-PrEP conducted 88 in-person interviews with women from the Truvada arm and had 224 women from both arms participate in computer-assisted self-interviews in order to learn more about why a high proportion of the study population lied about their pill use.

In the computer interviews, 31 percent of the women admitted to over-reporting their adherence rate during the trial, most commonly because they were worried about being cut out of the trial. The medical care the women received as a part of the trial may have been a primary motivating factor behind their participation. The second most common reason given for lying was that it was easier simply to say that they had been taking their pills. The next most common reason for lying was that the women feared the trial staff would be disappointed in them if they didn’t adhere.

Thirty-five percent of the participants said they had discarded pills in order to fool the trial investigators at clinic visits, when they were to bring back whatever pills they had remaining in order for the investigators to deduce adherence rates. Four percent said they had given pills away, either to HIV-positive friends or partners or to people with other health conditions they believed the pills would treat.

During the interviews, many of the participants said that other women in the study had thrown away pills in order to come off as adherent to the regimen.

To read the aidsmap story, click here.

To read the study abstract, click here.