A Multi-Modal Mobile Phone-Based Communication Strategy to Maximize Retention in a Post-Intensive Care Follow-up Study of Acute Respiratory Distress Syndrome Survivors.

Background: Retention of critical illness survivors in longitudinal studies is challenging but essential to minimizing selection bias. Contact via telephone and mail may be less effective in the era of text messaging using mobile phones. We designed, implemented, and evaluated mobile phone-based communication, rideshare coordination, and renumeration protocol to optimize retention among acute respiratory distress syndrome (ARDS) survivors. Methods: We conducted a single-center cohort study of adult ARDS survivors, assessing disability via surveys at hospital discharge, and at 3-, 6-, and 12-months. We also conducted performance-based measures and phlebotomy at hospital discharge and 3-months. We sent mobile phone-based text message reminders 14 and 8-11 days prior to each follow-up due date. We then contacted participants 7-10 days before their due date using telephone calls, text messages, or email, with proxies contacted when necessary. We provided mobile phone- or email-based remuneration at hospital discharge and 3-month clinic visits. For this clinic visit, we coordinated transportation using a mobile phone rideshare application, including accessible options for participants with mobility limitations. Results: Participants were a median [IQR] 61 [43-69] years old; 32% were Black, 30% were Spanish-speaking, and 31% had less than high-school education; 20% had psychiatric comorbidity, and 19% had alcohol or drug misuse. Among 60 eligible survivors, we achieved 96-98% retention at 3, 6, and 12-month follow-up telephone visits, and 80% retention at 3-month clinic visits. Participants completed the 3-, 6-, and 12-month telephone surveys with a median [IQR] of 1 [-3 to 8], 3 [-3 to 17], and - 1 [-6 to 8] days of the due date, with a median [IQR] of 1 [1 to 2] telephone calls for each follow-up. Median telephone call attempts and assessment timing did not differ by age, language, or educational attainment (all p > 0.05). Complete core physical function data were obtained at all assessments. Conclusion: A mobile phone-based communication strategy achieved high follow-up rates with minimal contact attempts and timely completion of assessments across diverse demographic groups. Rideshare coordination, including accessible transportation options, facilitated in-person retention for 3 months. These methods demonstrate a scalable approach to maximizing retention in longitudinal studies of ICU survivors.