BACKGROUND: Sustained adherence to antiretroviral therapy (ART) is essential for maintaining viral suppression among people with HIV (PWH), yet adherence fluctuates over time and is imperfectly captured by routine viral load monitoring in many settings where measurements are often infrequent. We aimed to identify longitudinal ART adherence trajectories using electronic dose monitoring (EDM) and assess their association with viral non-suppression in a South African cohort.
METHODS: We analyzed data from a prospective cohort of PWH in Cape Town, South Africa on tenofovir-based ART. Daily adherence was measured using EDM over 12 months and summarized as monthly counts of dose events. Group-based trajectory modelling was applied to monthly adherence proportions to identify distinct adherence patterns. Associations between trajectory membership and time to viral non-suppression (HIV-1 RNA > 50 copies/mL) were assessed using Kaplan–Meier methods and log-rank tests.
RESULTS: Among 238 PWH, 5 adherence trajectories were identified: persistently high (49.6%), gradually declining (22.7%), delayed declining (9.6%), rapidly declining (8.0%), and consistently suboptimal adherence (10.1%). Rapidly declining and delayed declining trajectories were associated with earlier and higher incidence of viral non-suppression compared with persistently high and gradually declining trajectories (log-rank p < 0.001). Younger PWH were more likely to be in lower-adherence trajectories; baseline psychosocial characteristics did not differ across groups.
CONCLUSIONS: ART adherence is dynamic and heterogeneous; early declines in electronically measured adherence are associated with increased viral non-suppression risk. Longitudinal adherence trajectories may offer clinically actionable signals before routine viral load testing, informing differentiated HIV care programmes.
Longitudinal adherence trajectories measured by electronic dose monitoring and viral non-suppression in a South African HIV cohort study
BMC Infectious Diseases [Epub 2026 Jun 11]. doi: 10.1186/s12879-026-13690-z.