ABSTRACT
INTRODUCTION: The best method to measure adherence to antiretroviral therapy (ART) in resource-limited settings has not yet been established, particularly among adolescents and young adults (AYAs). The use of mobile technology may address the need for standardized tools in measuring adherence in this often marginalized population. METHODS: We conducted a cross-sectional validation study among AYAs (18-35 years) attending a South African HIV clinic between 07/2015-09/2017. We determine the diagnostic accuracy of two modes of delivering an adherence questionnaire (self-administered electronic vs interviewer-administered paper-adherence questionnaire) comprising two self-reported adherence tools (South African National Department of Health (NDoH) adherence questionnaire and the Simplified Medication Adherence Questionnaire (SMAQ)) to identify poor adherence compared to; 1) a detectable viral load (≥1000 copies/mL) and 2) a sub-optimal concentration of efavirenz (EFV) (EFV ≤1.00 µg/mL) measured by therapeutic drug monitoring (TDM). RESULTS: Of 278 included participants, 7.1% and 7.3% completing the electronic- and paper-questionnaires had a detectable viral load, while 14.7% and 16.5% had a sub-optimal concentration of EFV, respectively. According to viral load monitoring, the electronic-adherence questionnaire had a higher sensitivity (Se) in detecting poor adherence than the paper-based version across the NDoH adherence questionnaire (Se: 63.6% vs 33.3%) and SMAQ (Se: 90.9% vs 66.7%). In contrast, when using blood drug concentration (EFV ≤1.00 µg/mL), the paper-adherence questionnaire produced a higher sensitivity across both adherence tools; namely the NDoH adherence questionnaire (Se: 50.0% vs 38.1%) and SMAQ (Se: 75.0% vs 57.1%). CONCLUSION: When using more accurate real-time measures of poor adherence such as TDM in this young adult population, we observe a higher sensitivity of an interviewer-administered paper-adherence questionnaire than an identical set of self-administered adherence questions on an electronic tablet. An interviewer-administered questionnaire may elicit more accurate responses from participants through a sense of increased accountability when engaging with health care workers.