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Chronic Fatigue & CFS valid clinical entities across countries/healthcare settings?

Dolphin

Senior Member
Messages
17,567
In the case of the technique used here, Factor Analysis, there's a lot of user input/judgement required, which is probably why the authors saidDifferent groups could have taken the same data and come up with 4 or 6 factors, and they could all be right, ie it's a matter of opinion - to some extent (with 4, 5 or 6 factor solutions, 4 of the factors would be very similar across all solutions). For that reason, Factor Analysis findings shouldn't be seen as absolute.

It's notable that the authors 'Inflammation' factor included both sharp chest pains and dizziness, neither of which is obviously linked to inflammation (and neither of which is part of Fukuda), which helps to illustrate how the factors are not exactly absolute.
Yes, one should always be a little wary of the categories in factor analysis. The headings can sometimes make things sound more neat than they actually are or, to put it another way, as you point out in this occasion, the elements may not neatly fit under the arbitrarily named heading for the factor.
 

Dolphin

Senior Member
Messages
17,567
As an aside the question of scientists as sub-standard statisticians has come up a couple of times recently. As not all scientists can be expected to be expert statisticians, why is it not standard practice to pass data for statistical analysis by statisticians, rather by the researchers themselves? Is there a valid reason, or is it just historical?
(Speculating) Peer review is generally an activity that one doesn't get paid for. Given that expert statisticians would only make up a small percentage of all scientists, they would be greatly overworked if a statistician was required for each paper.

On biomedcentral, open access reviews are the norm/very common.

Each reviewer seems to be asked whether it needs a statistical review. This is the normal response:
Statistical review: No, the manuscript does not need to be seen by a statistician.

I think a problem may be that people are reluctant to admit they don't know something properly e.g. some sort of statistical analysis technique. So when something seems ok/the authors "sell it" well, they let it through.

I agree with you that it is frustrating.
 

WillowJ

คภภเє ɠรค๓թєl
Messages
4,940
Location
WA, USA
I don't necessarily see Fukuda as conflating CF with CFS. The whole strategy of Fukuda is to specifically exclude a whole number of known causes of CF, then to apply a severity threshold (of sorts), and then requires a set of required symptoms (even if it's not a satisfactory set of symptoms). If I'd had the energy, I was going to point out in my original post that this 2009 Hickie paper differs from Fukuda precisely by conflating CFS with CF, and even with prolonged (1 month+) fatigue. Which is quite a shocking thing to do when their own evidence actually points to Fukuda being too broad.

Sorry, I was unclear. The recommendations (don't test for b-z, use CBT/GET, etc.) are based on conflating CFS with CF. Review papers and Meta-analysis using Fukuda-CFS and Oxford-CFS and Empiric-CFS and Hickie-CFS and Holmes-CFS, for that matter, (and on rare occasions, Canadian-ME/CFS) as if all of those referred to the same kind of patient (and when used by various groups who may apply them differently, referred to the same kind of patient), when in fact some of them are just plain CF (and sometimes PF, <6 months), regardless of what name they put on the criteria and the studies.
 
Messages
13,774
The lack of a coherent factor structure ties in with an earlier paper by Hickie (which also contributed about half the patients used in the CFS-only analysis above) that concluded.

Just going through this thread, and noticed that this earlier paper is no longer on-line.

Looks like it was taken down:

http://www.vipbg.vcu.edu/~nathan/publications/

To be honest, this stuff is making my head swim, but I thought I'd point this out in case anyone had a copy that should be put on-line.
 
Messages
13,774
Just going through this thread, and noticed that this earlier paper is no longer on-line.

Looks like it was taken down:

http://www.vipbg.vcu.edu/~nathan/publications/

To be honest, this stuff is making my head swim, but I thought I'd point this out in case anyone had a copy that should be put on-line.

Arrgh... I was just about to make exactly the same post again. I didn't remember any of this thread! I only replied last May. Oh well. Thanks for the interesting points OB.