Continuous Wrist-Worn Accelerometry Captures Change In Average Daily Step Count In People With Multiple Sclerosis Over One Year

Objective: To measure STEPS (average daily step count) captured over 1-year in people with multiple sclerosis using a commercially-available wrist-worn accelerometer (Fitbit Flex). Background: More granular disability metrics are needed to advance research in MS. The Expanded Disability Status scale (EDSS), fails to capture important variability in walking behavior within categorical ambulatory disability levels that can affect function and influence health. STEPS measured using remote accelerometry provides granular, continuous information about physical activity in real-world settings. Design/Methods: Adults with MS (relapsing or progressive) able to walk at least 2 minutes were prospectively recruited into the UCSF FITriMS cohort. Physical activity was recorded continuously using a Fitbit Flex over 1 year and data collected using the UCSF Health eHeart research platform. Performance-based measures (e.g. EDSS, Timed-25-foot-walk; T25FW) were evaluated at baseline and 1-year, and patient-reported outcomes (e.g. 12-item MS walking-scale; MSWS-12) were completed at baseline, 1.5, 3, 6, 9 and 12-months. Univariate and multivariable analyses were performed. Results: Of 96 participants (61 relapsing MS, 35 progressive MS), 79 have completed 1-year follow-up (retention 82.3%); 9 withdrew, and 8 were lost to follow-up. Over 1 year, for the entire cohort, STEPS decreased 10.7% (mean decrease: 1236 steps/day, SD: 3065), and 53.4% decreased STEPS more than 800 steps/day (a proposed Minimal Clinically Important Difference threshold). Average STEPS in people with progressive MS declined less (0.2% decline from baseline, mean: −903, SD: 2239) than in those with relapsing MS (16.5% decline from baseline, mean: −1413, SD: 3436). There was wide variability in STEPS change over 1 year, including in people whose EDSS remained unchanged (for example, for people who remained EDSS 6.0 change in STEPS ranged from +814 to −3718). Conclusions: Longitudinal measurement of STEPS using a commercially-available activity monitor is feasible with high retention, revealing changes in daily function not otherwise captured by more traditional disability metrics. Study Supported by: National Center for Advancing Translational Sciences of NIH (KL2TR000143) (JMG) Disclosure: Dr. Block has nothing to disclose. Dr Bove has nothing to disclose. Dr. Keshavan has nothing to disclose. Dr. Zhao has nothing to disclose. Dr. Bevan has nothing to disclose. Dr. Crabtree-Hartman has received research support from has received educational grants from the MS Foundation, Teva neurosciences, and Biogen. She has served as a consultant to Genzyme, Teva and Novartis. She is on the Speakers Bureau for Genzyme, Teva and Biogen. Dr. Graves has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Biogen. Dr. Green has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Dr. Green has received personal compensation for activities with Inception Sciences, Mylan Pharma, Medimmune, and Bionure. Dr. Green has received personal compensation in an editorial capacity for Dr. Green has received personal compensation for serving on the board of Inception Sciences. Dr. Green has received research support from Dr. Green has received research support from Inception Sciences, Biogen, and Novartis. Dr. Pletcher has nothing to disclose. Dr. Olgin has nothing to disclose. Dr. Marcus has nothing to disclose. Dr. Allen has nothing to disclose. Dr. Cree has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Abbvie, Biogen, EMD Serono, GeNEuro, Novartis, Sanofi Genzyme. Dr. Cree has received research support from Acorda, Hoffman La Roche, MedImmune, Novartis, Receptos and Teva. Dr. Gelfand has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with .