Electronic measurement of adherence to pediatric antiretroviral therapy in South Africa

Background: Little is known about adherence to pediatric antiretroviral regimens in countries of the developing world. Both assessment methods and predictors of adherence need to be examined to deliver appropriate health care to the growing patient population in resource-limited settings. Methods: We conducted a prospective study of adherence in a pediatric HIV outpatient clinic in Cape Town, South Africa. Adherence was assessed by the Medication Event Monitoring System (MEMS) and caregiver self-report by Visual Analogue Scale (VAS). Virologic response was recorded at study baseline and closest follow-up visit, child and caregiver data were collected by questionnaires. Results: For 73 children followed, median adherence by MEMS was 87.5%, median caregiver reported adherence was 100%. MEMS and caregiver report differed in reporting excellent (> 95%) adherence, with MEMS classifying 36% of subjects in this category, whereas caregiver report classified 91%. Overall, 65% of children achieved virologic suppression after the study period. MEMS adherence was significantly associated with virologic suppression. The highest specificity was obtained when adjusting the data for doses taken at the prescribed time (91.3%). No predictors for the differences between MEMS and caregiver reported adherence could be identified. Conclusions: Adherence to pediatric antiretroviral regimens in South Africa is not lower than in the developed world, yet not high enough to guarantee long-term treatment success. Caregiver report seems unreliable in this setting. MEMS is a feasible and accurate measure of adherence for children on liquid drug formulations.