Post-Exertional Malaise May Be Related to Central Blood Pressure, Sympathetic Activity and Mental Fatigue in CFS Patients, 2021, Kujawski et al

Kujawski, Julia Newton et al

Abstract
Post-exertional malaise (PEM) is regarded as the hallmark symptom in chronic fatigue syndrome (CFS). The aim of the current study is to explore differences in CFS patients with and without PEM in indicators of aortic stiffness, autonomic nervous system function, and severity of fatigue. One-hundred and one patients met the Fukuda criteria. A Chronic Fatigue Questionnaire (CFQ) and Fatigue Impact Scale (FIS) were used to assess the level of mental and physical fatigue.
Aortic systolic blood pressure (sBPaortic) and the autonomic nervous system were measured with the arteriograph and Task Force Monitor, respectively. Eighty-two patients suffered prolonged PEM according to the Fukuda criteria, while 19 did not. Patients with PEM had higher FIS scores (p = 0.02), lower central systolic blood pressure (p = 0.02) and higher mental fatigue (p = 0.03). For a one-point
increase in the mental fatigue component of the CFQ scale, the risk of PEM increases by 34%. For an sBPaortic increase of 1 mmHg, the risk of PEM decreases by 5%. For a one unit increase in sympathovagal balance, the risk of PEM increases by 330%. Higher mental fatigue and sympathetic activity in rest are related to an increased risk of PEM, while higher central systolic blood pressure is related to a reduced risk of PEM. However, none of the between group differences were significant after FDR correction, and therefore conclusions should be treated with caution and replicated in further studies

https://science.rsu.lv/en/publicati...e-may-be-related-to-central-blood-pressure--2

 

Ugh. Makes this study useless.

 

Open access, as part of the digital edition of the book "Chronic Fatigue Syndrome/Myalgic Encephalomyelitis, Diagnosis and Treatment", https://www.mdpi.com/books/book/6613

 

I don't understand why researchers seemingly quite familiar with ME use the Fukuda criteria.

 

No, it's "nuanced". I think I'll call all useless studies that.

 

In this particular case Fukuda is sensible because Fukuda allows comparing people with and without PEM (with the stricter criteria all participants have PEM, at least in theory) and the comparison is the whole point of this study.

I wish every study using Fukuda would analyse the with and without PEM groups separately. There could be important clues hiding in that comparison.

So Fukuda is fine in this case. Though there is no excuse whatsoever for the CFQ

[Have only read the abstract]

 

I expect better. Listing your conclusions, then ending it with "it's not really statistically significant" is the scientific equivalent of a clickbait ad saying "If your dog licks its paws every day, do this" that links to an hour-long video that pitches an overpriced supplement 50 minutes in.

 

Shame isn't it that the response you'd expect from a profession with a positive attitude to the lesson of the new Nice guideline process would be to improve the validity of sample and measures (as well as design of course).

It's pretty sad to see the whole non-pharm list of studies [in the guideline appendix] and realise they all are non-direct and without certainty of everyone having the right condition - which seems probably the most basic thing of a study into an illness. Imagine studying whatever for hayfever and failing at the first hurdle of making sure everyone you recruited actually had hayfever. And explaining that to laypersons without being allowed to hide it under tricky language.

They'd surely be pulling a bit of a face as the penny dropped when they said something like 'so you mean you forgot that element so anyone whose runny nose got better over the week of the study could just have been because they had a cold?....... not very useful hey'

It isn't the hardest or biggest thing in any study for them to have straightened this bit out so it feels so sad and without excuse the sector didn't pull themselves together and just at least quietly start using the right bits for selection at least (even if they did quietly ignore the rest)

 

Bit hard for them to know the lessons of the new NICE guideline before the guideline process even got started.

And as Trish points out if you actually look at the study there is some value to it.

 

It diminishes the results too much. It's really not too much to expect better, although CFQ is what IMO makes it less relevant. It's such a bad choice that reveals several probable additional awful choices that aren't as obvious.

These people are professionals. I think we should expect professionals to do quality work that avoid flaws like this. Every other discipline manages this. It's just always disappointing to see it happen, there's no reason for it. It's already hard enough to compare studies and results when you add those weird mistakes.

If those results are to be of any use, they will have to be replicated in a proper study using better criteria and instruments. Probably more than once. That adds years to a process that doesn't have to drag on like this, there are so few shots to use as it is, shooting blanks really doesn't help us when 90%+ of the research in the field is completely useless.

 

OK I didn't actually realise this study was done finishing in 2018? I meant/said reply to the new guideline - granted then this particular study couldn't have been changed but it does raise some interesting mind-bends on how does it slot in that seem pertinent to a lot right now.

But I think the questions it is flagging up as begging for the sector are the same ie I'm noting that the guideline doc shows that this is an issue, and a sensible response to looking through all of those studies in that guideline doc that have criteria that mean you don't know if people have PEM/PESE/ME/CFS. How can a table or heuristic of criteria be made for any old stuff to slot even something like this in?

So no I think my comment is correct that I don't know how the sector wouldn't need to be somewhat getting together to make sure these issues are confirmed/addressed so theoretically the next ten years of research can at least conclude as being different because they worked out how to make sure it was the right illness and what aspects were involved use consistent definitions of PEM etc.

It might be badly put that the 'easy' bit is once you have a definition/terms signed off for it then to be used vs 'pick your own version', the hard bit/big questions being getting what could be used consistently confirmed, agreed, defined - and as the terms in this show, some of the 'loose ends' resolved satisfactorily in order to start tightening the terms used.

And I have seen the 'some value' of they tested for PEM and compared with non-PEM within this, so there is a 'PEM test'.

It is suggesting 'CFS patients without PEM' because it uses Fukada, and highlights some of the ongoing terminological conundrums that does need some overarching group clarifying and resolving surely going forwards? What, if they were being diagnosed today, would/should their condition actually be termed as?

And as a past one does it provide us with useful info if we are just 'looking at the PEM group' but still taking the results comparatively to this?