David Bangsberg, MD, MPH, from Harvard Medical School shared some data and insights from his groundbreaking work on adherence during a global scale-up symposium on Tuesday afternoon. He pointed out that both levels and patterns of adherence are important, and that the critical period for adherence is likely early in treatment when viral suppression is being established.
Dr. Bangsberg reminded the audience that notwithstanding initial views that antiretroviral therapy (ART) adherence would be low in resource-limited settings, adherence levels in these settings in fact are higher than they are in rich countries. He referenced an important study by Ware and colleagues published in 2009 in PLoS Medicine. The study describes the notion of social capital. In resource-limited settings, structural and economic issues are the major drivers to non-adherence. Many patients have to ask friends and family for help in accessing care and medication, and so a commitment to taking their medication becomes part of the social compact that is established between the patient and the community that supports them. Stigma can be a huge barrier in this regard, because without the ability to disclose status, one cannot ask for help.
Since adherence tends to deteriorate over time, Bangsberg described several interventions to increase adherence, including weekly text message reminders that have been shown to be quite effective. He also highlighted some research that suggests that pharmacy refill adherence may be a better predictor of virologic failure than CD4 monitoring. Generally, there is a three- to four-day window to intervene with patients who have not received or taken their drugs before the risk of virologic failure becomes very high. Adherence support improves health outcomes and saves money.
Bangsberg identified the current monetary resources challenges as a great threat to adherence. He referenced a study in 2010 PLoS One, by Geng, et al., looking at the dramatic reduction in the availability of public treatment slots in Uganda beginning in 2009. Wait time for ART quickly increased from 55 to 90 days. Bangsberg expressed grave concern that in environments of treatment instability, the same kinds of social supports that have facilitated adherence could become a powerful force for sharing medications – thereby increasing drug resistance and treatment failure.