...discrepancies between objective and subjective measurement of the physical activity level in female patients with [CFS], 2021, Vergauwen et al

Full title: An exploratory study of discrepancies between objective and subjective measurement of the physical activity level in female patients with chronic fatigue syndrome

Highlights
• There is a discrepancy between self-report and objective activity measures in CFS.

• The activity diary cannot replace objective monitoring systems, i.e. accelerometry.

• Age is negatively associated with the discrepancy in both cases and controls.

• No demographic factors, illness-related complaints or HRQOL explain the discrepancy.

Abstract
Objective
To explore the ability of a self-report activity diary to measure the physical activity level (PAL) in female patients with chronic fatigue syndrome (CFS) and whether illness-related complaints, health-related quality of life domains (HRQOL) or demographic factors are associated with discrepancies between self-reported and objectively measured PAL.

Methods
Sixty-six patients with CFS, recruited from the chronic fatigue clinic of a university hospital, and twenty matched healthy controls wore an accelerometer (Actical) for six consecutive days and registered their activities in an activity diary in the same period. Participants' demographic data was collected and all subjects completed the CFS Symptom List (illness-related complaints) daily and Short-Form-36 (HRQOL domains) during the first and second appointment.

Results
A significant, but weak association between the activity diary and Actical was present in patients with CFS (rs = 0.376 and rs = 0.352; p < 0.001) and a moderately strong association in healthy controls (rs = 0.605; and rs = 0.644; p < 0.001) between week and weekend days, respectively. A linear mixed model identified a negative association between age and the discrepancy between the self-reported and objective measure of PA in both patients with CFS and healthy controls.

Conclusion
The activity diary showed limited ability to register the PAL in female patients with CFS. The discrepancy between measures was not explained by illness-related complaints, HRQOL domains or demographic factors. The activity diary cannot replace objective activity monitoring measured with an accelerometer, but may provide additional information about the perceived activity.

Paywall, https://www.sciencedirect.com/science/article/abs/pii/S0022399921000623

 

Does this mean that the results of the PACE trial are unreliable?

 

Ha ha. Touché!

 

Out of all the journals this study could have been published in, I am surprised that it appeared in the Journal of Psychosomatic Research. And it comes just days after the other case study on blinding in a homeopathy trial for CFS.

Are we going to see more articles on evidence quality in this journal that would debunk prior work from its advisory board members (Fink, Rosmalen, White, Sharpe, Stone - and the only French associate editor, Lemogne, supports GET for CFS)?

@Woolie mentioned that the new editor of the journal, Jess Fiedorowicz, is pushing for more rigorous reviews of BPS papers. If it is truly happening, then this looks like a (cautiously) promising start.

ETA: In order to provide reliable evidence, investigators of trials of GET for CFS should have conducted this study before starting any such trial. Instead, they decided without evidence that subjective reports of physical activity would be valid, even though they were aware of concerns around this issue. This further questions their scientific integrity.

 

No it means that middle-age women are not to be trusted when reporting their symptoms

 

Doesn't that mean that there is less of a discrepancy between the self-reporting and the measurement in the older women? So the older women are more accurate in their perception/reporting? And was the length of time that they'd had ME/CFS taken into account?
And why was this a single-sex study?

 

Perhaps the new editor is taking the name of the journal seriously - for research that is really all in the minds of the researchers.

 

This puzzled. I guess they are simply reporting that weekday activities and weekend activities are statistically more similar to other days in the same subset than in the other.

 

To (probably mis)quote something I saw not long ago: I do not question their scientific integrity, I reject its existence.

 

There are two r values for CFS and two for controls so isn't that they looked for one correlation amongst all weekdays and another for all weekend days, for each subject group, presumably because they thought the correlations might be rather different? So the correlations were better for healthy controls.

 

Yes

 

It would be interesting to see the full text and know in which way the relationship of objective and subjective measurements exactly differed in each group and between the groups.

I have no reason to doubt the correctness of their conclusion:

I'd like to know though whether there was a clear tendency towards over- or underestimating activity.

Also, what kind of activities did they investigate?

Is it possible that the accelerometers that were applied don't measure particular movements/ activities/ inactivities with the same accuracy as other movements/ activities? So that the differences in accuracy of perceived activity might rather reflect an inaccuracy of the objective measures due to the fact that patients just have different movement patterns?

 

To me it suggests people are working during the week?