Activity monitoring and patient-reported outcome measures in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients.

Abstract

INTRODUCTION: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disease with no validated specific and sensitive biomarker, and no standard  approved treatment. In this observational study with no intervention,  participants used a Fitbit activity tracker. The aims were to explore natural  symptom variation, feasibility of continuous activity monitoring, and to compare  activity data with patient reported outcome measures (PROMs). MATERIALS AND  METHODS: In this pilot study, 27 patients with mild to severe ME/CFS, of mean age  42.3 years, used the Fitbit Charge 3 continuously for six months. Patients wore a  SenseWear activity bracelet for 7 days at baseline, at 3 and 6 months. At  baseline and follow-up they completed the Short Form 36 Health Survey (SF-36) and  the DePaul Symptom Questionnaire-Short Form (DSQ-SF). RESULTS: The mean number of  steps per day decreased with increasing ME/CFS severity; mild 5566, moderate 4991  and severe 1998. The day-by-day variation was mean 47% (range 25%-79%). Mean  steps per day increased from the first to the second three-month period, 4341 vs  4781 steps, p = 0.022. The maximum differences in outcome measures between 4-week  periods (highest vs lowest), were more evident in a group of eight patients with  milder disease (baseline SF-36 PF > 50 or DSQ-SF < 55) as compared to 19 patients  with higher symptom burden (SF-36 PF < 50 and DSQ-SF > 55), for SF-36 PF raw  scores: 16.9 vs 3.4 points, and for steps per day: 958 versus 479 steps. The  correlations between steps per day and self-reported SF-36 Physical function,  SF-36 Social function, and DSQ-SF were significant. Fitbit recorded significantly  higher number of steps than SenseWear. Resting heart rates were stable during six  months. CONCLUSION: Continuous activity registration with Fitbit Charge 3  trackers is feasible and useful in studies with ME/CFS patients to monitor steps  and resting heart rate, in addition to self-reported outcome measures. CLINICAL  TRIAL REGISTRATION: Clinicaltrials.gov: NCT04195815.