What we know and what we do not know about factors associated with and interventions to promote antiretroviral adherence.

Antiretroviral therapy (ART) adherence remains critical for achieving successful outcomes. Factors affecting ART adherence can occur at the individual level or be related to the treatment regimen, daily schedule, and/or interpersonal relationships. While treatment-related barriers have diminished with recent simplified ART regimens, guidelines still recommend considering regimen simplicity. ART readiness should be assessed prior to starting ART, with follow-up adherence assessments once ART is initiated, and at all subsequent clinical visits. Adherence interventions work best when multifaceted, targeted for at-risk and nonadherent participants, and tailored to individuals' needs. Successful interventions have included education and counseling, provision of social support, directly observed therapy, and financial incentives. Pillboxes and two-way short-text messaging service (SMS) reminders have been shown to be effective and are widely recommended tools for promoting ART adherence. Further research is needed to determine the optimal combination of adherence interventions, as well as generalizability, implementation, and cost-effectiveness.