3845 The future of clinical trials? Monitoring mobility as an outcome measure in Parkinson’s disease: the Mobilise-D study

Abstract Introduction A key challenge in clinical trials targeting disease modification in Parkinson’s disease (PD) is the lack of sensitive, precise, and patient-relevant outcome measures. Digital mobility outcomes (DMOs), captured using body-worn devices, offer a novel, objective means to assess real-world gait and mobility—domains often impaired early in PD. The Mobilise-D consortium was established to develop and validate DMOs in PD and other chronic conditions. The objective of this work was to describe DMOs in a large, representative international cohort of individuals with PD and compare to controls and across disease stage; and to determine compliance and feasibility. Methods As part of the Mobilise-D Clinical Validation and Extension Studies, real world mobility of individuals with PD (n = 601) and matched controls (n = 232) was assessed using a single wearable device for seven days. Data were processed to yield 24 technically validated DMOs, representing different domains of real-world walking and mobility performance. Results DMO data were available for 531 PD and 223 controls. Significant differences between the groups were observed in 20 of 24 DMOs. Compared to controls, PD participants exhibited shorter daily walking duration and lower step counts, walking at a higher cadence and in fewer walking bouts per day. Findings also varied by disease severity, with differences observed particularly between controls vs. mild (Hoehn and Yahr stage I-II) and mild vs. moderate (Hoehn and Yahr stage III) disease. Compliance rates were high. Conclusion Distinct DMO patterns across PD severity and between PD and controls support their utility as sensitive, scalable outcome measures for future clinical trials and therapeutic development.