An in-home engagement and usability study of GeRI: An open-source platform for remote symptom assessment and wearable activity monitoring in men with prostate cancer

Abstract

Geriatric assessment (GA) is underused in oncology because clinic-based implementation is time-and resource-intensive, limiting routine evaluation of frailty and treatment tolerance. Existing digital tools often rely on proprietary devices and closed analytic pipelines. We developed the Geriatric Remote Initiative (GeRI), an open-source platform integrating a wrist-worn accelerometer, smart scale, and tablet interface with reproducible analytics and triggerable surveys. GeRI was evaluated in a 12-week home deployment in 10 men aged ≥65 years receiving androgen-deprivation therapy for prostate cancer. Self-rated health (SRH) and symptom surveys triggered 48-hour accelerometry windows, initiated by pressing "Start monitoring" on the watch. Engagement was defined a priori as completion of ≥50% of prompted interactions (surveys, scale readings, and watch-session initiation) within each 4-week block; prespecified engagement was met (9/10 participants in all three blocks). Usability was assessed using the System Usability Scale (SUS) (range 57.5–100; 8/10 ≥75). Across the first three 4-week blocks, survey and scale completion was high (86–87% and 83%) while watch-session initiation occurred in 65% of prompts. Initiated windows could contribute up to 80 recoverable 24-hour intervals; 43 met validity criteria (≤1.5 h non-wear and ≥300 steps/day), and one participant contributed 0 valid intervals despite initiating all watch prompts due to non-wear. Candidate frailty-aligned metrics included steps (inactivity), cadence (slowness), longest walking bout (endurance), and activity intensity; exploratory analyses suggested that comorbidity and polypharmacy aligned with lower activity and higher quality of life with greater intensity. GeRI's open-source architecture supports GA-aligned home monitoring and motivates refinements to improve data yield.