Abstract Background Electronic monitoring devices (EMDs) may provide an objective method for assessing medication adherence. However, evidence on their validity compared to other adherence measures, their functional feasibility, and their acceptability, especially among adolescents, remains limited. Adolescents face multifaceted adherence challenges, yet there is a lack of evidence to inform the use of digital tools for adherence monitoring and support in this age group, particularly in low-income settings. We assessed feasibility, acceptability, and validity of an EMD among adolescents enrolled in the multi-country clinical trial VITALITY. Methods An explanatory sequential mixed methods study was embedded within the Zimbabwean site of the VITALITY trial, a randomised controlled trial evaluating weekly vitamin D supplementation on bone health in adolescents living with HIV. A random sample of 97 participants (aged 11–19 years) was provided an EMD for 24 weeks to monitor adherence to vitamin D or placebo. Validity was assessed by correlating EMD-measured adherence with serum vitamin D levels. Feasibility of the EMD was investigated through records of battery duration, network connectivity, and EMD malfunction. Seventeen participants were purposively selected for qualitative exit interviews to explore acceptability and reasons for discordance between adherence measured through the EMD and pill count. Results Ninety-seven participants, median age 16.7 (interquartile range13.5, 18.7) years, 50 (51.5%) female were provided with the EMD for a median of 24 (range 22–25) weeks. There was a strong positive correlation between EMD-measured adherence and week-48 vitamin D levels (β = 0.63, 95% CI: 0.42–0.85; R 2 = 0.42; p < 0.001), supporting the validity of EMD data as a proxy for medication intake. The EMD functioned reliably despite intermittent network coverage, and no major malfunctions were reported. Adolescents found the EMDs highly acceptable due to their ease of use, discretion, and perceived motivational benefits. Conclusions This study demonstrates that EMDs are valid, feasible, and acceptable tools for monitoring adherence among adolescents in low-income settings. These findings support the potential for broader use of EMDs to promote and monitor adherence to long-term treatments in adolescents beyond research settings. Trial registration Pan African Clinical Trials Registry (PACTR), PACTR202009897660297 .
Dzavakwa et al. (2026) studied this question.