Exploratory study into the relationship between the symptoms of CFS/ME and fibromyalgia using a quasiexperimental design, 2021, McKay et al

John Mac

Senior Member (Voting Rights)
Full title: Exploratory study into the relationship between the symptoms of chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME) and fibromyalgia (FM) using a quasiexperimental design

Abstract
Objective To explore the relationship between symptoms of chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME) and fibromyalgia (FM). The hypothesis predicated that there would be no significant differences between the group’s symptom experience.

Design A quasiexperimental design. Structural equation modelling (SEM) and invariance testing.

Participants Males (M) and females (F) >16 with a confirmed diagnosis of CFS/ME or FM by a general practitioner or specialist. CFS/ME (n=101, F: n=86, M: n=15, mean (M) age M=45.5 years). FM (n=107, F: n=95, M: n=12, M=47.2 years).

Outcome measures Diagnostic criteria: the American Centers for Disease Control and Prevention (CDC) for CFS/ME and the American College of Rheumatology (ACR) criteria for FM. Additional symptom questionnaires measuring: pain, sleep quality, fatigue, quality of life, anxiety and depression, locus of control and self-esteem.

Results Invariance was confirmed with the exception of the American CDC Symptom Inventory, Fibromyalgia Impact Questionnaire and Hospital Anxiety and Depression Scale (p<0.05) based on five questions. Consequently, it was erroneous to conclude differences. Therefore, the Syndrome Model was created. SEM could not have tested the ACR previously, as it comprised a single data point. Thus, it was combined with these three questionnaires, increasing the data points, to create this new measurable model. Results confirmed no significant differences between groups (p=0.07 (p<0.05)).

Conclusion Participants responded in a similar manner to the questionnaire, confirming the same symptom experience. It is important to consider this in context with differing criteria and management guidelines, as this may influence diagnosis and the trajectory of patient’s management. With the biomedical cause currently unclear, it is the symptom experience and the impact on quality of life that is important. These findings are meaningful for patients, clinicians and policy development and support the requirement for future research.

https://bmjopen.bmj.com/content/11/2/e041947
 
They didn't look at post-exertional malaise, the term doesn't appear once in the text. They didn't separate participants into ME only, FM only, or ME/CFS and FM.

Why they're omitting PEM and still using the Fukuda criteria when the CDC has moved on to the IOM criteria is beyond my understanding.

They should have used the DePaul questionnaire instead of the CDC's CFS symptom inventory, too.

Are they doing this on purpose to confirm their hypothesis, and maybe justify that care pathways for ME/CFS and FM can be merged? That's the only reason I can think of.
 
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Am I missing something here? Is this the most idiotic piece of research yet?

Take two conditions with some overlap in symptoms, and some differences.
Ignore the differences and only give both groups questionnaires about the symptoms they have in common.
Analyse the results and conclude they are the same.

So that's like: let's ask a group of giraffes and a group of mice to fill in questionnaires about whether they have hairy bodies, 4 legs and give birth to live offspring. Oh, magically they both come out the same. Conclusion: giraffes are the same as mice.
 
Yes, but how do they rate on magazine questionnaires about which Beatles they are? Is it more significant than rating which K-pop band they are more alike? Or what their zodiac sign says about their career prospects. Results will shock you!

This practice of using arbitrary questionnaires of no relevance and deciding that those questionnaires are now the judge and jury of millions of people's is quite literally criminally insane. The questionnaires are fully generic, they have no applicability here.
 
Yes, but how do they rate on magazine questionnaires about which Beatles they are? Is it more significant than rating which K-pop band they are more alike? Or what their zodiac sign says about their career prospects. Results will shock you!

This practice of using arbitrary questionnaires of no relevance and deciding that those questionnaires are now the judge and jury of millions of people's is quite literally criminally insane. The questionnaires are fully generic, they have no applicability here.
they even point out the flaw of using arbitary questionnaires funny world when you can publish this whilst pointing towards your own failings .
 
Quasi-experimental means that they control all variable, perhaps except whether the practicing physician who diagnoses knows the difference between ME and FM and are able to determine whether the patient has one or the other, or both.
 
Especially nowadays when the tests for fibro have become so loose they are almost meaningless. (Doctors complained about it at the time.)

More and more we see CFS and fibromyalgia treated as the symptoms of fatigue and widespread pain respectively.
 
Especially nowadays when the tests for fibro have become so loose they are almost meaningless. (Doctors complained about it at the time.)
In all other professions, and I know this for a fact is very prominent in the software industry, when something doesn't work we just go ahead and fix it instead of whining about it endlessly. Hell, in the software industry it's even common to do it for free! People just straight up take it for themselves to write a solution to the problem and simply shares it, source and all, with the whole world. And not just small problems, some become huge projects in their own right, sometimes worked on and maintained for years, all for free!

Not sure why medicine is different but they really should try that some day. I've never seen a profession so whiny about things directly under their control yet completely unwilling to do anything about it other than complaining some more.
 
All this suggests is the lack of specificity of the questionnaires and associated questionnaire answering behaviour in demarcating the conditions. The fallibility of the questionnaires has been regularly pointed out by patients, but it seems these researchers have not heard the message.
 
I accidentally posted this in the wrong thread (here) but it was a comment on this study:

The authors conclude:
our findings do not suggest that any single symptom, such as pain or fatigue, nor the magnitude of any similarities or differences between the individual symptoms are responsible for the cause, or any differences between CFS/ME and FM, but contribute to the whole symptom experience. This argument/conclusion is presented based on the evidence which highlights that to date, the aetiologies for both these groups have not been clearly identified, and therefore the symptoms of CFS/ ME and FM manifest as a single reality based on their responses to the questionnaires
99.1% of fibromyalgia patients said they had 'fatigue after exertion' but I don't think more stringent measures of PEM were used.

It also seems that participants did not undergo an extensive medical examination but simply had to mention that "they had a confirmed diagnosis of CFS/ME or FM by a GP or specialist". It is not clear if this was checked to be correct. One of the main differences between CFS and FM is that the former used more stringent exclusion criteria.
 
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