Clinical criteria versus a possible research case definition in chronic fatigue syndrome/ME

[Dolphin]

http://www.tandfonline.com/doi/abs/10.1080/21641846.2017.1299077?journalCode=rftg20

Fatigue: Biomedicine, Health & Behavior

Clinical criteria versus a possible research case definition in chronic fatigue syndrome/myalgic encephalomyelitis

Leonard A. Jason, Stephanie McManimen, Madison Sunnquist, Julia L. Newton & Elin Bolle Strand


Received 23 Dec 2016

Accepted 21 Feb 2017

Published online: 06 Mar 2017


ABSTRACT


Background: The Institute of Medicine (IOM) recently developed clinical criteria for what had been known as chronic fatigue syndrome.

Given the broad nature of the clinical IOM criteria, there is a need for a research definition that would select a more homogenous and impaired group of patients than the IOM clinical criteria. At the present time, it is unclear what will serve as the research definition.


Purpose: The current study focused on a research definition which selected homebound individuals who met the four IOM criteria, excluding medical and psychiatric co-morbidities.


Methods: Our research criteria were compared to those participants meeting the IOM criteria. Those not meeting either of these criteria sets were placed in a separate group defined by six or more months of fatigue. Data analyzed were from the DePaul Symptom Questionnaire and the 36-item Short-Form Health Survey (SF-36). Due to unequal sample sizes and variances, Welch’s F tests and Games-Howell post-hoc tests were conducted.


Results: Using a large database of over 1000 patients from several countries, we found that those meeting a more restrictive research definition were even more impaired and more symptomatic than those meeting criteria for the other two groups.


Conclusion: Deciding on a particular research case definition would allow researchers to select more comparable patient samples across settings, and this would represent one of the most significant methodologic advances for this field of study.

 

[Dolphin]

I found this a bit of an odd paper. It wasn't really much of a surprise I think that homebound patients would be more severely affected than the other 2 groups.

 

[Dolphin]

I think that researchers should start exploring adding together the symptom scores for ME/CFS symptoms and explore what thresholds might be useful for clinical and research criteria.

Table 3. Composite means for the IOM homebound research criteria (N = 1212).

Chronic fatigue (n = 304)
IOM (n = 708)
Research (n = 200)

has dozens of different symptoms. For all but 2 of them there is a statistically significant difference across the groups, mostly p<0.001.

The odd ones out are:
Feeling like you have a low temp (all around the same)
Sweating hands (an unofficial trend in the same direction as the other scores)

 

[Dolphin]

Fatigue goes away with rest ***

Chronic fatigue (n = 304)
IOM (n = 708)
Research (n = 200)

M (SD)

Entirely 3.4 (10) 0.0 (0) 0.0 (0)
Partially 53.9 (160) 46.0 (326) 25.0 (50)
Not improved by rest 41.8 (124) 54.0 (382) 75.0 (150)

I found this interesting. The Fukuda criteria say the fatigue should not be substantially improved by rest. This is often shortened to "not improved by rest" in the text of many research papers. I wonder what some researchers are doing with this.

I recall seeing in recent years that the CDC exclude patients if they said they were improved by rest, on a scale of 0 to 4, by 2 or more I think. This could exclude some genuine patients.

The NIH for their intramural study consulted with the CDC which might end up with them using a similar approach.

 

[Dolphin]

I found this a bit of an odd paper. It wasn't really much of a surprise I think that homebound patients would be more severely affected than the other 2 groups.

I think it would be a bit odd to have a research criteria which requires patients to be homebound. It could also make doing research difficult.

Of course it could be useful for the odd study, I just mean as the norm.

 

[Diwi9]

While I appreciate the sample size in this study, self-report measures are a problem for analyzing this disease. How are they able to identify and randomly sample the ME/CFS sufferers, without running into issues of under-diagnosis and over-inclusion? It seems like restricted access to healthcare means that it is the same patient cohort representing this disease in multiple studies. Also, sufferers' perceptions of their health and functioning can be impacted by so many variables, including the fact that this cohort likely has some level of medical attention.

 

[Esther12]

I recall seeing in recent years that the CDC exclude patients if they said they were improved by rest, on a scale of 0 to 4, by 2 or more I think. This could exclude some genuine patients.

In terms of how I feel, I improve a lot with rest. It's not curative, and doesn't allow me to then return to normal activity levels, but I can get to the point of not feeling that ill when I really don't have to do anything. That part of the Fukuda criteria has always been a bit confusing for me.

 

[Dolphin]

In terms of how I feel, I improve a lot with rest. It's not curative, and doesn't allow me to then return to normal activity levels, but I can get to the point of not feeling that ill when I really don't have to do anything. That part of the Fukuda criteria has always been a bit confusing for me.

That reminds me that this paper discusses it (one of the first times I've seen it discussed):

Regarding the criteria of ‘fatigue is not substantially alleviate by rest,’ if a person indicated that the person’s problem with fatigue/energy entirely went away with rest, they would be excluded. For the item involving ‘fatigue is the result of excessive exertion,’ Hu et al. [31] found that long working hours are correlated with burnout when working over 40 hours per week and is even stronger when working over 60 hours per week. Therefore, individuals who indicated that combined work related activities or household activities involved 60 or more hours a week, for the past 4 weeks, would be considered exclusionary

I think the criteria in Fukuda et al. were designed with this sort of scenario in mind but I'm concerned researchers don't necessarily use it that way. Also all the statements "CFS is not improved by rest" by the Fukuda definition must confuse some readers of research papers.

 

[Esther12]

Thanks for pulling that out.

I think the criteria in Fukuda et al. were designed with this sort of scenario in mind but I'm concerned researchers don't necessarily use it that way. Also all the statements "CFS is not improved by rest" by the Fukuda definition must confuse some readers of research papers.

Yes - that's what I think too. Intended as a way to exclude those suffering from chronic fatigue related to doing lots of work, but now seemingly open to misinterpretation. It is poorly phrased. Benefiting from rest after 10 minutes of cleaning is a bit different to being able to recover as a result of working over-time less often.

 

[TiredSam]

Results: Using a large database of over 1000 patients from several countries, we found that those meeting a more restrictive research definition were even more impaired and more symptomatic than those meeting criteria for the other two groups.

Isn't that completely obvious? A looser definition will include those less impaired and less symptomatic because of the looser definition - how could it be otherwise? Am I missing something?

 

[Sean]

Nope, you are not missing anything. This is the sort of nonsense they have built their careers on.

 

[Esther12]

Nope, you are not missing anything. This is the sort of nonsense they have built their careers on.

It's a Jason and Newton collaboration, and generally they don't seem to be pushing for ever looser criteria.

 

[Sean]

Oops. Apologies to Jason and Newton, I am getting threads mixed up.