Adherence to antiretroviral therapy in young children in Cape Town, South Africa, measured by medication return and caregiver self-report: a prospective cohort study

Background: Antiretroviral therapy (ART) dramatically improves outcomes for children in Africa; however excellent adherence is required for treatment success. This study describes the utility of different measures of adherence in detecting lapses in infants and young children in Cape Town, South Africa. Methods: In a prospective cohort of 122 HIV-infected children commenced on ART, adherence was measured monthly during the first year of treatment by medication return (MR) for both syrups and tablets/capsules. A questionnaire was administered to caregivers after 3 months of treatment to assess experience with giving medication and self-reported adherence. Viral and immune response to treatment were assessed at the end of one year and associations with measured adherence determined. Results: Medication was returned for 115/122 (94%) children with median age (IQR) of 37 (16-61) months. Ninety-one (79%) children achieved annual average MR adherence >= 90%. This was an important covariate associated with viral suppression after adjustment for disease severity (OR = 5.5 [95% CI: 0.8-35.6], p = 0.075), however was not associated with immunological response to ART. By 3 months on ART, 13 (10%) children had deceased and 11 (10%) were lost to follow-up. Questionnaires were completed by 87/98 (90%) of caregivers of those who remained in care. Sensitivity of poor reported adherence (missing = 1 dose in the previous 3 days) for MR adherence <90% was only 31.8% (95% CI: 10.7% -53.0%). Caregivers of 33/87 (38.4%) children reported difficulties with giving medication, most commonly poor palatability (21.8%). Independent socio-demographic predictors of MR adherence = 90% were secondary education of caregivers (OR = 4.49; 95% CI: 1.10 -18.24) and access to water and electricity (OR = 2.65; 95% CI: 0.93 -7.55). Taking ritonavir was negatively associated with MR adherence = 90% (OR = 0.37; 95% CI: 0.13-1.02). Conclusion: Excellent adherence to ART is possible in African infants and young children and the relatively simple low technology measure of adherence by MR strongly predicts viral response. Better socio-economic status and more palatable regimens are associated with better adherence.