Consumer-based activity trackers in evaluation of physical activity in myositis patients. (16th September 2021)

• Record Type: Journal Article
• Authors: Saygin, Didem; Rockette-Wagner, Bonny; Oddis, Chester; Neiman, Nicole; Koontz, Diane; Moghadam-Kia, Siamak; Aggarwal, Rohit
• Is Part Of: Rheumatology. Volume 61:Number 7(2022)
• Page Start: 2951
• Page End: 2958
• Publication Date: 2021-09-16
• Subjects: myositis -- Fitbit -- physical activity monitor; Rheumatism -- Periodicals; Rheumatology -- Periodicals; 616.723005
• DOI: 10.1093/rheumatology/keab700
• Languages: English
• ISSNs: 1462-0324

Abstract

Abstract: Objectives: Inflammatory myopathies are characterized by muscle weakness that limits the activities of daily living. Daily step count is an accepted metric of physical activity. Wearable technologies such as Fitbit ® enable tracking of daily step counts. We assessed the psychometric properties of Fitbit ® and compared the accuracy of Fitbit ® step counts to ActiGraph ® . Methods: This was a pilot, proof of concept, prospective observational study with four visits at 0, 1, 3 and 6 months in PM, DM, necrotizing myopathy (NM) or anti-synthetase syndrome (AS) subjects. Six core set measures (manual muscle testing, physician global disease activity, patient global disease activity, and extra-muscular disease activity, HAQ-Disability Index and creatine kinase), three functional tests (six-min walk, timed up-and-go, sit-to-stand tests) and SF-36 physical function-10 (PF10) were collected at each visit. Patients wore waist-worn Fitbit ® One and ActiGraph ® T3X-BT concurrently for 7 days/month for 6 months. Results: Twenty-four (10 DM, 8 PM/NM, 6 AS) patients (17 females/7 males; 91% Caucasian) were enrolled. Test-retest reliability of daily steps was strong in 1-month follow-up (ICC 0.89). Daily steps and peak 1-min cadence showed moderate-strong correlations with physician global disease activity, patient global disease activity, HAQ-Disability Index, SF-36 PF10 and all three functional tests. Fitbit ® and ActiGraph ® step counts demonstrated good agreement and strong correlation (ICC 0.96). Conclusion: Fitbit ® daily steps and peak 1-min cadence are reliable and valid measures of physical activity in a cohort of myositis patients. This pilot data suggests that Fitbit ® has a potential for use in clinical practice and trials to monitor physical activity in myositis patients, but larger studies are needed for further validation.