Efficacy of cognitive behavioral therapy targeting severe fatigue following COVID-19: results of a randomized controlled trial 2023, Kuut, Knoop et al

Yahoo: COVID fatigue: cognitive behavioural therapy could help people manage persistent symptoms – new research

The same article on the Conversation.

Written by Rhiannon Phillips, a health psychologist from Cardiff Metropolitan University

 

And now the same article has also been published on the Gavi Vaccines Work website where we have already seen at least one particularly bad BPS-oriented article on ME/CFS recently.

 

Yesterday, I sent some comments to Hans Knoop and Tanja Kuut on potential issues with the data in Table 3 and presentation of results in Fig 2.

I have asked that they consider addressing these points—which may well be explainable—before the paper is published in final form. Lets see if they do that!

Obviously, there are other issues—such as the trial protocol and philosophy behind the study—that have been raised here. I just focused on some things that don't make sense to me.

 

PS I would really like to know if the first point—about the repetitive standard error values in Table 3—can be explained, if there's anyone here with a good background in clinical stats...

 

Yes this can't be right. Must be an error of some kind.


It also doesn't make sense to report the standard error (SE) instead of the standard deviation (SD) for the values at baseline.

Because we know that the sample size n for each group was 57, we can calculate the SD as SE times the square root of n. For example for the baseline value of the CBT group, SE = 0.5, n = 57 so: SD = 3.775. That value is also surprisingly low. The authors assumed a SD of 12 in their power calculation.

 

Yep the SD would be 3.775 for CIS-fatigue in the CBT group (SE=0.5), much lower than 12.

 

How was this not picked up by peer review (or people tweeting enthusiastically about the study)...

 

Perhaps you should write to the journal editors or ask the help of data sleuths such as Nick Brown or Health Nerd on Twitter.

 

I did think of doing the latter. I just don't want to take liberties.

 

This is used to calculate the error on the between-group difference. The SE we have flagged are on individual groups (i.e., calculated before that stage), so this shouldn't matter.

 

The pooled standard deviation is just for estimating the effect size, the Cohen's D.

I'm far from an expert myself but really think these are errors.

 

If it's not too much trouble, @ME/CFS Skeptic, are you able to resend this image with the repeated SEs at T0 also highlighted. There is one instance. Cheers.

 

One question I have: the title says 'Estimated means and linear mixed model analyses....'

What do they mean by this? Are they showing results from some extra modeling step?

EDIT: And why are T1 and T2 means referred to as 'Estimated means', whereas the baseline value at T0 is just 'mean'? There could be a subsequent step that means the means (and their SEs) are somehow modelled.

 

This is the key part of the text explain the method to achieve the values in Table 3. It seems convoluted to me, and perhaps these numbers are 'modelled'. But, if this is the case, why not just use the actual values!

 

Another possibility is that the means are estimated at T1 and T2 because the true means cannot be calculated due to dropouts (but they can be calculated at baseline). This is apparently what intention-to-treat analysis deals with.

 

Yes the means post-treatment are estimated means and accounting for the correlation of multiple measurements by the same person ('repeated measurements were nested within participants') might have reduced variability.

But in my view it would not explain why the SE are the same for 9 out of 10 outcome measures post-treatment. It also doesn't help explaining why they report SE for the baselines values instead of a SD.

EDIT: Intention-to-treat might explain why they report modelled results but it is still weird to report the SE for baseline values and it also would not explain the similarities in SE between groups.

Might be wrong but still think an error is the most likely explanation.

 

I submitted correspondence to the editor about this paper.

I'll let you know how that goes

 

The study is mentioned by Dr. Griffin in the latest clinical update from TWiV. He seemed persuaded by it. At 17.55: