Consumer-based activity trackers in evaluation of physical activity in myositis patients

Abstract

Objectives Inflammatory myopathies are characterized by muscle weakness that limit 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 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 4 visits at 0, 1-, 3-, and 6-months in polymyositis (PM), dermatomyositis (DM), necrotizing myopathy (NM) or anti-synthetase syndrome (AS) subjects. Six core set measures [manual muscle testing, physician (MD-GDA), patient (PT-GDA), and extra-muscular disease activity, HAQ-DI and creatine kinase], 3 functional tests [six-minute 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 MD-GDA, PT-GDA, HAQ-DI, 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.

Quality of life in patients with myositis is associated with functional capacity, body composition, and disease activity—Baseline data from a randomized controlled trial

“…[35][36][37] to strong positive between habitual physical activity levels measured by accelerometers and longitudinal changes in clinical outcomes for patients with myositis, as improvements in the habitual physical activity levels coincided with improvements in MMT8, HAQ, and PhGD. 24,38,39 Self-perceived physical function assessed by HAQ appeared to be among the most influential factors (strongest predictors) on physical quality of life in the present study. Similar findings have been observed previously 40 and reaffirm that HAQ is a vital measure in the monitoring of patients with myositis.…”

“…Both subjectively (IPAQ) and objectively (accelerometery) physical activity was unrelated to physical and mental quality of life, suggesting that high or low levels of physical activity may not per se be sensitive factors in the monitoring of patients with stable myositis in relation to concurrent assessments/interventions on quality of life. However, some studies have observed moderate to strong positive between habitual physical activity levels measured by accelerometers and longitudinal changes in clinical outcomes for patients with myositis, as improvements in the habitual physical activity levels coincided with improvements in MMT8, HAQ, and PhGD 24,38,39 …”

Effectiveness and safety of immunoadsorption as a rescue treatment of inflammatory myopathies: report of three cases and literature review

“… 22 Most studies across the subgroups of IIM found that CK levels do not correlate with muscular function. 23 – 26 …”

Wearables in der Rheumatologie

“…Ein Zusammenhang zwischen der Muskelkraft und dem Aktivitätsprofil konnte jedoch nicht nachgewiesen werden [ 30 ]. Eine prospektive Beobachtungsstudie mit 24 Patient:innen mit inflammatorischen Myopathien konnte eine Korrelation der täglichen Schrittzahl sowie maximalen 1‑min-Schrittfrequenz mit der Einschätzung der Krankheitsaktivität durch Arzt und Patient, dem HAQ-Behinderungsindex, SF-36 PF10 sowie verschiedenen Funktionstests (6-min-Gehtest, Timed up-and-go, Sit-to-Stand-Test) zeigen [ 31 ].…”