Design, Recruitment, and Enrollment for EPI-LoVE: A US-based National Virtual Cohort of People Living with HIV at Risk for Viral Non-Suppression (Preprint)

<sec> <title>BACKGROUND</title> <p>Despite substantial advances in HIV treatment, many people living with HIV (PLWH) fail to achieve or maintain viral suppression. Individuals who experience interruptions in HIV care, adherence challenges, and viral non-suppression are often underrepresented in traditional clinic-based cohort studies because of geographic, transportation, social, and healthcare access barriers. Virtual cohort methodologies offer opportunities to recruit, engage, and retain these populations while integrating longitudinal behavioral, biomarker, and digital engagement data needed to characterize dynamic changes in HIV care engagement and viral suppression.</p> </sec> <sec> <title>OBJECTIVE</title> <p>The Exploring, Predicting, and Intervening on Long-Term Viral Suppression Electronically (EPI-LoVE) study was developed to establish a national virtual cohort of PLWH who are currently not virally suppressed, have a history of viral non-suppression, or are at elevated risk for future viral non-suppression. We describe the study design, recruitment and participant verification procedures, data collection methods, retention strategies, and baseline cohort characteristics.</p> </sec> <sec> <title>METHODS</title> <p>Participants were recruited through digital advertising, a national HIV care provider network, and referrals from previous research studies. Eligible participants were adults living with HIV who were currently virally unsuppressed or considered at elevated risk for future viral non-suppression based on a history of detectable HIV viral load, recent missed HIV care appointments, or a qualifying mental health diagnosis. Following standardized online screening, participant eligibility was confirmed through telephone verification and review of supporting documentation. Participants completed online surveys every three months and HIV viral load assessments every six months over 24 months. Data were collected through a study-specific mobile health platform integrating longitudinal behavioral surveys, remote biomarker collection, app engagement metrics, and frequent "Speak Up" micro-assessments of time-varying behavioral and psychosocial factors associated with HIV care engagement and viral suppression.</p> </sec> <sec> <title>RESULTS</title> <p>Between February 2024 and July 2025, 4,789 individuals expressed interest in the study, of whom 2,739 completed screening and 2,262 met eligibility criteria. A total of 1,109 participants consented, and 1,051 enrolled. Among eligible participants, 63.4% qualified based on a self-reported detectable viral load during the previous 12 months, whereas the remainder qualified based on recent missed HIV care appointments or a qualifying mental health diagnosis. The cohort was predominantly Black or African American (64.5%), with a median age of 36 years; 77.0% reported recent substance use and 63.7% screened positive for moderate-to-severe depressive symptoms. Baseline HIV viral load data were obtained from 863 participants (82.1%).</p> </sec> <sec> <title>CONCLUSIONS</title> <p>EPI-LoVE demonstrates the feasibility of recruiting, verifying, and engaging a geographically diverse national virtual cohort of PLWH at elevated risk for viral non-suppression. By integrating longitudinal behavioral assessments, biomarker collection, and digital engagement data within a single platform, EPI-LoVE provides a scalable framework for studying the dynamic determinants of HIV care engagement and informing future personalized digital interventions.</p> </sec>