Exploring the validity of the chalder fatigue scale in chronic fatigue syndrome - 1998 Morriss et al

(Mods, do what you will with this.)

This paper from 1998 is regularly cited in various papers as showing that the CFQ is a reliable measure for CFS research.

But read beyond the abstract..........

https://www.sciencedirect.com/science/article/abs/pii/S0022399998000221

so they were recruiting for a trial

http://sci-hub.tw/https://doi.org/10.1016/S0022-3999(98)00022-1#

 

Write up looking at the CFQ in Occupational Medicine (2014)

https://academic.oup.com/occmed/article/65/1/86/1433061

 

I cannot see how this scale could EVER be taken seriously.

Look at the instructions, and think like a patient.

To what should the patient be comparing their symptoms “in the last month”?

Should it be compared to “when last well” or to “usual”? The header says to “usual”.

So, a patient who has just undergone treatment will quite possibly think that their 2nd taking of this questionnaire is to compare how they feel after treatment, to their “usual” state before treatment.

Hence a treated patient might answer that they have a symptom “no more than usual” - ie they think they are reporting that the treatment hasn’t changed their “usual” symptoms! (& Where is the “no LESS than usual” option?)

BUT those analysing the questionnaires will read a “no more than usual” response to mean, NO MORE THAN WHEN LAST WELL! - ie they will record the patient as recovered!!!

Think about this.... when first taking a this questionnaire, the patient might have no difficulty thinking that “usual” means “when well”, because they just have two states to consider. Being well, and being ill.

However when the patient takes the questionnaire the 2nd time after a treatment (perhaps months later) they now have THREE health states to consider: Being well, being ill, and the state they are in after treatment.

Now see how easy it is to create confusion for the responses. “Than Usual” in the header of each response means it is a mental leap every time to recognise that “usual” actually means “when well”.

What a mess. Whey not just put “when well” in the headers?

(Couple minor edits for clarity)

 

Just to clarify, this questionnaire, by its very nature, is setting patients up to declare a full recovery on a treatment that has zero effect.

 

Does anyone know if they have changed it from usual nowadays?

 

Inevitably it's the questions they don't ask that are relevant to our situation and illness.

 

I searched online to find the questionnaire, and looked at several places where it is available. All use “usual”.

I think were that changed, it would need to be described as a modified version of the CFQ?

I really don’t understand how this questionnaire ever passed the first glance from some-one other than the author. The confusion would be so simply cleared up by putting “when last well” in each of the headers instead of the word “usual”.

So it really begs the question, WHY did that not happen?


And another thing - there is no option for “No change”, or “no less than usual” - the closest option for the patient using the questionnaire and wanting to declare no change, being the “No worse than usual” option.

Thus the phrasing for the patients duped into ticking this box (thinking about how they are comparing their current state to their “usual” illness state) will read exactly the way that the researchers want.

That then means they can record “recovery” from a treatment, just because the box ticked is interpreted by them as meaning “No worse than when last well”. (No matter what the patient thought they were recording!)


In other words, the use of this “no more than usual” phrasing as the “no change” option means these patients are easily reported as RECOVERED in the outcomes from the trial. This is also a sleight of hand in my view!

 

The lack of rigour in drafting something like this sums the whole BPS lot up really.

Some of the questions asking 'more' or 'less', when the answers are more/less options anyway.

If "you have been feeling tired for a long while", and your brain is fried as part of your symptoms, how well are you going to remember what it felt like when you were last well anyway? I suspect the therapist's advice might be "Oh, just do the best you can" ... !

 

Yes I was going to say the same thing. I've seen the chalder scale before but it pulled me up short again when I did that survey - just because it's such an utterly stupid way of describing - leading to all the issues you describe @Unable . Since she is a professor it's difficult to believe she is lacking in IQ department, therefore one has to wonder if Chalder (et al) are just being deliberately obtuse, or if it is, as suggested, intentional.

 

It is impossible to fathom why they thought this was a good scale.

Why is there not a section for mild fatigue or moderate fatigue?

They seem to think it is a good thing that so many people cluster at the high end.

How can a scale be good if everyone scores the maximum? Why not extend it?

Then using "usual". Anyone reading measurements using this scale will assume it is like a pain scale, a measure of how fatigued a person feels. They will assume the measure is against no fatigue or normal everyday fatigue. Any pain scale which just measures how much pain you are in compared with usual would find cancer patients scored near the low end while someone with a splinter will score high.

It couldn't be that they deliberately want a scale to back up their theories

 

Yes, I guess it doesnt always follow. I just meant i expect a certain level of intelligence if someone has made it through to that stage in their academic life. However I think this issue is more to do with common sense, & thinking it through, than anything else so it may not follow...

 

I got sick in my early 20s. I am now in my mid-50s.

I have been sick (with no remissions) for much longer than I was healthy.

How am I supposed to remember accurately what it felt like to be healthy?

 

You also only have to look at ps to know that high IQ is not uncommonly allied with zilch common sense.

 

Like you I have been ill so long I can't remember but they are not specifically asking you to compare with what you were like when you were well, we are just assuming that. They are asking as usual which means the way things usually are - I can't think of another way to say "usual" it means what it means.

So you have to try to work out what they are asking before you can answer and who knows what anyone is thinking. It is unbelievable!

 

And it's not as if there were countless studies showing how unreliable memory is. Might as well ask people to guesstimate how much they think they weigh in mushrooms as part of a weight loss trial. What mushrooms? Dry? Freshly picked? Cut? Washed? Exactly.

A more relevant question would be how accurate it is. The answer to that is obvious but then that's not the point of this questionnaire at all.

 

To be fair, in the Liv Uni study mentioned above (where the Chalder scale is included) it did say at the beginning - sorry I cant remember the exact words - but words to the effect of 'if you've been ill a long time answer compared to when you last felt well'.

But I don't think, IIRC, that that clarification is always given, which makes it even sillier & less interpretable between studies.

 

I think the general wording of the scale is of interest in that all the questions are really psychological questions - what you feel, what you need, what your problems are. The assumption is that 'fatigue' is a self-value judgment rather than a symptom as such. For arthritis we do not ask 'Do you have problems with pain?'. We have a pain level score and the patient creates their own baseline that they can refer to.