LOS ANGELES – The commercially available Fitbit Flex accelerometer proved useful and feasible for longitudinal measurement of average daily steps in a prospective, 1-year study of patients with multiple sclerosis.
Dr. Valerie J. Block
The wrist-worn device was well received, with 79 of 96 participants (82%) completing follow-up, and it revealed changes in daily functioning that were not captured using more traditional disability metrics, Valerie J. Block, DPTSc, reported at the annual meeting of the American Academy of Neurology.
The study involved 61 adults with relapsing multiple sclerosis (MS) and 35 with progressive MS who were recruited into the University of California, San Francisco (UCSF) FITriMS cohort. All were able to walk at least 2 minutes at baseline, and their daily physical activity was recorded continuously by the device over 1 year. Performance-based measures, including the Expanded Disability Status Scale (EDSS) and timed 25-foot walk test, were evaluated at baseline and at 1 year, and patient-reported outcomes such as the 12-item MS walking scale were completed at baseline and at 1.5, 3, 6, 9, and 12 months. Nine patients withdrew, and eight were lost to follow-up.
“This was a fairly stable, actively treated cohort, and overall, there was no significant change in average daily steps (STEPS) over 1 year. However, there was a trend toward a decrease (–315 steps/day; P = .117), and 53% of patients had a decrease of more than 800 steps per day, which is a proposed minimal clinically important difference threshold,” Dr. Block, a postdoctoral scholar at UCSF, said in an interview.
Despite the modest, gradual reduction in STEPS over the year, most participants were able to complete the study, providing at least 1 valid week of STEPS data per month throughout the year, she said, noting that there was no difference in device use between relapsing MS and progressive MS participants.
A significant association between decreasing STEPS and worsening of clinic-based and patient-reported outcomes was demonstrated, but declining STEPS occurred even when disability levels, as measured by the EDSS, remained stable.
“Participants who started off the study with lower STEPS, below the cohort median of 4,766 STEPS, had fourfold higher odds of clinically-meaningful disability worsening at 1 year after adjusting for age, sex, and disease duration,” she said.
Further, earlier data published by Dr. Block and her colleagues showed there is wide variability in the change in steps over 1 year. In that study, the change in step count in patients whose EDSS score remained unchanged ranged from +814 to –3,718, suggesting that popular mainstream wearable technology is not only feasible but also can provide a more detailed and nuanced measure of how patients are functioning in their daily lives, she said.
Together, these findings suggest that remote accelerometry provides useful continuous information about physical activity in real-world setting, she said, concluding that “these results support the possibility of using STEPS as a more sensitive and granular outcome measure in clinical trials and for targeted interventions in clinical care.”
This study was supported by the National Center for Advancing Translational Sciences. Dr. Block reported having no disclosures.
SOURCE: Block VJ et al. Neurology. 2018 Apr 10;90(15 Suppl):N5.001.