Adaptive Text Messaging and Non-Monetary Incentives to Sustain ART Adherence Among Adolescents Living With HIV in Ethiopia

ART adherence will be measured using a multi-method composite adherence assessment tool based on previously validated measures, including self-reported adherence, pill count (PC), and retention in care (missed appointments). Self-reported adherence will be assessed through four validated yes/no questions addressing difficulties remembering medication, intentional discontinuation when feeling better or worse, and missed doses over the preceding four days. Participants will also rate their adherence over the past 30 days using a visual analogue scale (VAS) ranging from 0 (no adherence) to 10 (perfect adherence). Each adherence component will be dichotomized using established thresholds (≥95% adherence for self-report, pill count, and VAS; no missed appointments for retention in care) and assigned a score of 1 (adherent) or 0 (non-adherent). Component scores will be summed to generate a composite adherence index ranging from 0 to 3, which will be reported as a single adherence measure ca

Implementation Outcomes: The delivery, uptake, and integration of the adaptive SMS reminder and non-monetary incentive intervention will be evaluated by assessing six key implementation outcomes: acceptability, feasibility, fidelity, adoption/uptake, penetration/reach, and sustainability/maintenance.

Description of Outcome Measures:

Acceptability: Measured using the validated Acceptability of Intervention Measure (AIM) and supplemented with in-depth qualitative interviews with participants regarding the intervention's content, timing, and incentives. Assessment timepoints: 3, 6, 9, and 12 months.

Feasibility: Evaluated through digital logs of SMS delivery, records of incentive distribution, and semi-structured interviews with clinic staff to identify barriers, facilitators, and ease of implementation. Formally assessed at 6 and 12 months, with continuous process monitoring.

Fidelity: Assessed by comparing the planned intervention protocol

The proportion of adolescents living with HIV who maintain a viral load below 1,000 copies/mL at the 12-month study visit, assessed as the primary clinical effectiveness outcome of the adaptive SMS and incentive intervention

This study will perform a comprehensive economic evaluation from both healthcare system and societal perspectives. The analysis will compare the incremental costs and health outcomes of the combined adaptive SMS reminder and non-monetary incentive intervention against the standard of care. Cost-effectiveness will be assessed as the incremental cost per additional adolescent achieving sustained ART adherence. Cost-utility will be measured as the incremental cost per Quality-Adjusted Life Year (QALY) gained, with health utilities derived from the EQ-5D-Y/3L instrument administered at baseline, 6, and 12 months. We will calculate Incremental Cost-Effectiveness Ratios (ICERs) and conduct sensitivity analyses to assess uncertainty. A budget impact analysis will model the financial consequences of potential scale-up.

This study will measure a comprehensive set of patient-level factors hypothesized to influence sustained adherence to antiretroviral therapy (ART) among adolescents living with HIV. Validated self-report scales will be used to assess habit strength, intrinsic motivation, HIV-related stigma, depressive symptoms, and perceived social support.

Rationale for Measurement Schedule:

Baseline: To establish initial levels, identify baseline predictors of subsequent adherence and viral load suppression/rebound, and allow for statistical adjustment of participant differences.

3-Month Follow-up: To detect initial changes in psychosocial factors and investigate early mediators of adherence behavior following intervention initiation.

6-Month Follow-up (Midline): To track short-term trends and identify adaptation or emerging challenges in adherence behavior.

9- and 12-Month Follow-ups: To assess the longer-term trajector

Patient-level determinants, including habit strength, intrinsic motivation, HIV-related stigma, depressive symptoms, and social support, will be measured using validated self-report scales at baseline, 3, 6, 9, and 12 months. Baseline: Establish initial levels, identify predictors of adherence and viral suppression and its rebound, and allow adjustment for participant differences. Early follow-up (3 months): Detect initial changes and early mediators of adherence. Midline (6 months): Track short-term trends, adaptation, and challenges in adherence behavior. Later follow-ups (9 and 12 months): Assess longer-term changes and maintenance of psychosocial factors. These measures will be analyzed as potential mediators or moderators of sustained ART adherence and viral load suppression.