Intervention With WhatsApp Messaging to Compare the Effect of Self-designed Messages and Standardized Messages in Adherence to Antiretroviral Treatment in Young People Living With HIV in a Hospital in Lima, Peru: Randomized, non-blinded Control Trial (Preprint)

BACKGROUND Young people living with HIV (PLWH) struggle to adhere optimally to antiretroviral therapy (ART). Most mobile messaging interventions to improve ART adherence have relied on SMS, with limited targeting of specific behavioral mechanisms. MHealth interventions for improving ART adherence designed based on behavioral change techniques (BCT) could increase effectiveness by targeting specific drivers, such as customization. WhatsApp facilitates the uptake of BCTs through different features. To improve ART adherence, we hypothesize that WhatsApp messages self-designed by participants, with spontaneous targeting of BCTs, could be more effective than standard WhatsApp messages designed by the researchers. OBJECTIVE Evaluate the effectiveness of WhatsApp messages created by participants (self-designed) compared to WhatsApp messages created by the researchers (standardized) over adherence to ART at 16 weeks of intervention in young PLWH who receive HIV care under routine conditions at a public hospital in Lima, Peru. METHODS Two-arm randomized controlled trial (RCT) with a parallel assignment of 1:1, with no blinding of study intervention. Eligible participants are consenting PLWH aged 18-29 who receive HIV care at the study center and whose mobile phones support WhatsApp. After enrolment, participants complete a survey about general/clinical information and preferences for the weekly schedule and the number of WhatsApp messages to be received. Participants are then randomized to the control group (messages designed by the research team) or to the experimental group (messages designed by participants), stratified by sex, educational level, current ART intake, and history of ART abandonment. In both arms, and through WhatsApp, participants receive (i) up to three weekly messages during sixteen weeks after enrolment for the delivery of the intervention; (ii) the Simplified Medication Adherence Questionnaire (SMAQ) at 4, 8, 12, and 16 weeks of intervention to analyze the primary outcome (self-reported ART adherence); and (iii) monthly questionnaires about the user’s experience. Throughout the study, the bidirectional design of WhatsApp chats enables participant-initiated communication with the medical research team. We will compare ART adherence at 16 weeks in both study groups under the intention to treat principle; we will not conduct an interim analysis. For bilateral alpha of 0.05, study power of 78.9%, and an expected size effect of 10% difference in self-reported ART adherence after 16 weeks, the calculated sample size is 120; the final was increased to 131 to conduct a two-week pilot. RESULTS In March 2024, we started enrolling and randomizing participants. The study follow-up will continue until the last participant completes 16 weeks of intervention (November 2024). Blinded data analysis will be completed by December 2024. CONCLUSIONS This trial will compare the effectiveness of standardized vs. self-designed WhatsApp messages over ART adherence measured at 16 weeks among young people living with HIV receiving routine care in a low-resource setting in Lima. CLINICALTRIAL ClinicalTrials.gov NCT06500013; https://clinicaltrials.gov/ct2/show/NCT06500013