Physical activity measures in patients with myalgic encephalomyelitis/chronic fatigue syndrome: correlations between peak oxygen consumption, the physical functioning scale of the SF-36 questionnaire, and the number of steps from an activity meter
Background most studies to assess effort intolerance in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have used questionnaires. Few studies have compared questionnaires with objective measures like an actometer or an exercise test. Therefore three measures of physical activity in ME/CFS patients, being the physical functioning scale (PFS) of the SF-36, the number of steps/day (Steps) of an actometer and the %peak VO 2 of a cardiopulmonary stress test were compared.
Methods female ME/CFS patients were selected from a clinical database if the three types of measurements were available, and the interval between measurements was ≤ three months. Data of the three measures were compared by linear regression.
Results in 99 female patients the three different measures were linearly, significantly and positively correlated (PFS vs Steps, PFS vs %peak VO 2 and Steps vs %peak VO 2 : all P<0.001). Subgroup analysis showed that the relations between the three measures were not different in patients with versus without fibromyalgia and with versus without a maximal exercise effort (RER≥1.1). In 20 patients re-evaluated for symptom worsening, the mean of all three measures was significantly lower (P<0.0001), strengthening the observation of the relations between them. Despite the close correlation a large variation was observed between the three measures in individual patients.
Conclusions given the large variation in ME/CFS patients, the use of only one type of measurement is inadequate. Integrating the three modalities may be useful for patient care by detecting overt discrepancies and may aid study designs aimed at improving exercise capacity.
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Posted 01 Jun, 2020
On 23 May, 2020
On 22 May, 2020
On 22 May, 2020
On 02 May, 2020
Received 28 Apr, 2020
Received 25 Apr, 2020
On 17 Apr, 2020
Invitations sent on 16 Apr, 2020
On 16 Apr, 2020
On 09 Apr, 2020
On 08 Apr, 2020
On 06 Apr, 2020
On 04 Apr, 2020
Physical activity measures in patients with myalgic encephalomyelitis/chronic fatigue syndrome: correlations between peak oxygen consumption, the physical functioning scale of the SF-36 questionnaire, and the number of steps from an activity meter
Posted 01 Jun, 2020
On 23 May, 2020
On 22 May, 2020
On 22 May, 2020
On 02 May, 2020
Received 28 Apr, 2020
Received 25 Apr, 2020
On 17 Apr, 2020
Invitations sent on 16 Apr, 2020
On 16 Apr, 2020
On 09 Apr, 2020
On 08 Apr, 2020
On 06 Apr, 2020
On 04 Apr, 2020
Background most studies to assess effort intolerance in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have used questionnaires. Few studies have compared questionnaires with objective measures like an actometer or an exercise test. Therefore three measures of physical activity in ME/CFS patients, being the physical functioning scale (PFS) of the SF-36, the number of steps/day (Steps) of an actometer and the %peak VO 2 of a cardiopulmonary stress test were compared.
Methods female ME/CFS patients were selected from a clinical database if the three types of measurements were available, and the interval between measurements was ≤ three months. Data of the three measures were compared by linear regression.
Results in 99 female patients the three different measures were linearly, significantly and positively correlated (PFS vs Steps, PFS vs %peak VO 2 and Steps vs %peak VO 2 : all P<0.001). Subgroup analysis showed that the relations between the three measures were not different in patients with versus without fibromyalgia and with versus without a maximal exercise effort (RER≥1.1). In 20 patients re-evaluated for symptom worsening, the mean of all three measures was significantly lower (P<0.0001), strengthening the observation of the relations between them. Despite the close correlation a large variation was observed between the three measures in individual patients.
Conclusions given the large variation in ME/CFS patients, the use of only one type of measurement is inadequate. Integrating the three modalities may be useful for patient care by detecting overt discrepancies and may aid study designs aimed at improving exercise capacity.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6