Fitbit as an activity monitor in idiopathic inflammatory myopathy: results from a real-world cohort.

Compliance with the Fitbit wear protocol was very high in IIM patients across both remote and in-person recruitment cohorts.

• Participants were asked to use their wrist-worn Fitbit for 7 consecutive days per month over 6 months.
• The study enrolled 120 IIM patients across two cohorts: a Tele-Research Cohort (TRC, n=82, remote enrolment) and a Centre-Based Cohort (CBC, n=38, in-person enrolment).
• Compliance results were similar for remote or local recruitment, suggesting PAMs are viable in telehealth settings.

Average daily steps per minute and average peak 1-minute cadence showed strong test-retest reliability in IIM patients.

• Average steps/min test-retest reliability: r=0.89 (p<0.0001).
• Average peak 1-minute cadence test-retest reliability: r=0.86 (p=0.0001).
• These two measures were the primary PAM variables evaluated.

Physical activity metrics from the Fitbit showed a longitudinal significant positive correlation with patient-reported and functional outcome measures.

• Functional and patient-reported outcome measures were completed monthly over the 6-month study period.
• A longitudinal significant positive correlation was found between physical activity metrics and both patient-reported and functional measures.
• This supports the validity of Fitbit PAM measures as indicators of disease activity and quality of life in IIM.

Gender, race/ethnicity, and disease subtypes were not associated with PAM measures in this IIM cohort.

• The cohort was 75% female, 81% White, with a mean age of 55.5±13.43 years.
• Disease subtypes included 51% dermatomyositis (DM), 39% polymyositis (PM), and 9% necrotising myopathy (NM).
• The TRC and CBC cohorts were similar in demographics and disease subtypes.
• None of these demographic or disease subtype variables were associated with average steps/min or average peak 1-minute cadence.

The MyPACER study successfully enrolled 120 IIM patients across two cohorts in a multi-centre observational prospective design.

• MyPACER (Myositis Patient Centred Tele-Research) was conducted over 6 months at multiple centres.
• Total enrollment: 120 IIM patients; 82 in the TRC (remote) and 38 in the CBC (in-person) groups.
• Patient population: mean age 55.5±13.43, 75% females, 81% White.
• The study included patients with dermatomyositis, necrotising myopathy, and polymyositis.