Patterns of PrEP Adherence in Men Who Have Sex with Men

One of the most important advances in health care has been the advent of pre-exposure prophylaxis, or PrEP. Typically offered to individuals at high risk of contracting HIV, studies have shown that it offers almost complete protection against transmission when taken consistently. Getting those at high risk to take PrEP consistently, however, is sometimes a challenge.

A team of researchers at the University of California San Diego conducted a study of 181 men who have sex with men to determine which subgroups adhered to their PrEP regimens and which subgroups had more difficulty. The subjects, who were judged to be at high risk of HIV acquisition, were patients at 4 clinics in southern California who were randomly assigned to receive reminder text messages as part of a larger study of PrEP.

The subjects were given doses of oral tenofovir disoproxil fumarate plus emtricitabine, with instructions to take the drugs at a prescribed time every day. They were then sent different text messages every day at the times they were supposed to take the drugs. The men were asked to respond to these texts by indicating either that they had taken the drugs, that they hadn't taken the drugs, or by pressing a "snooze" option, in which case they received a reminder text 1 hour later. Over a period of 48 weeks, the researchers monitored the men for compliance with this regimen.

Overall, adherence as measured by drug concentrations in the blood was fairly high. However, the scientists found significant differences between groups of varying demographics. Subjects whose adherence was somewhat lower than the group reporting the highest adherence were more likely to be younger, while the subjects with the lowest level of adherence tended to be nonwhite. This group tended to report a greater number of depressive symptoms and to have substance use problems. They also were less likely than the subjects who had the greatest adherence to express the belief that PrEP was an effective method of HIV prevention.

"Patients with more significant adherence challenges may benefit from additional intervention approaches such as motivational interviewing or motivational enhancement therapy," David J. Moore, PhD, professor of psychiatry at University of California San Diego and a co-author of the study, told Contagion^®. "For those with significant adherence difficulties, the barriers to adherence need to be identified and overcome, and the factors supporting adherence need to be reinforced. All persons, regardless of the medication that they may be taking, are likely to benefit from linking medication taking with other behaviors that are done on a daily basis, such as brushing teeth and eating breakfast. That's how habits are built."

Dr Moore and his team would like to see text messaging become a standard part of providers' tool boxes. "Text messaging is a low-cost, low-burden method for helping patients to monitor PrEP adherence," he said, adding that changing things up keeps patients interested. "Text messages that use varying content, such as those used in our intervention, increase engagement. The same message sent daily will work for some people but will become stale and ineffective for others."

Ms. Saloman is a health writer with more than 20 years of experience working for both consumer-and physician-focused publications. She is a graduate of Brandeis University and the Medill School of Journalism at Northwestern University. She lives in New Jersey with her family.