Scartozzi, Sunnquist, Jason (2019). ME/CFS case definitions: Effects of requiring a substantial reduction in functioning.

From Leonard Jason's FB wall:

 

sci-hub link

 

Two comments:

1/ They missed the most important effect of "requiring a substantial reduction in functioning" which is that more mildly affected patients don't get an early diagnosis and with it appropriate advice about pacing and so risk becoming worse.

2/ This doesn't seem right: Well above a third of the ill controls in the study supposedly met CCC and ICC, requiring participants to report PEM. Even some of the healthy controls met the criteria which makes me wonder how healthy they actually were.

I suspect what they were really measuring was post-exertional fatigue, not post-exertional malaise.

Their ill control group included lupus, MS, post-polio and cancer. I know people with all those conditions and all of them have post-exertional fatigue to some degree, some quite badly. But none of them have post-exertional malaise.

 

I am not sure that post-polio (or post-SARS or post-whatever-infectious-disease) is a different disease from ME.

I am sure that people with lupus, MS, RA, and other diseases can have post-exertional fatigue, but I don't know what other symptoms some of them might have. I mostly hear about fatigue and pain, but I have not done or read a systematic survey.

I think if we define post-exertional malaise very carefully, it might be unique to us, but I don't think we have the evidence to say for sure. Some people who thought they had ME with PEM have been diagnosed with other things and think the new diagnosis suits better.

So I don't think we can be sure of anything yet, except that fatigue or even post-exertional fatigue is a bad sorter for ME/cfs.

 

Merged thread

https://www.ncbi.nlm.nih.gov/pubmed/31788347 A paper on on if removing 'substantial reduction' from the diagnostic criterai is useful.

Does anyone find 'substantial reduction' stigmatising? Even if it did originate in psychological diagnosis. (?)

As the conclusion states - with some case definitions - specifically CCC and IOM - the cost of removing it is small.
(But I'm not sure why you'd want to).

 

It has sometimes been said that fatigue is a continuum and that ME/CFS just forms an artifical part at the severe end. Patients are very ill because case definitions require them to be.

So if I remember correctly, this paper was relevant in showing that requiring a substantial reduction in functioning does not fully explain why ME/CFS patients are so ill, as in some case defintions this apparentlh changes little to the selection of patients.

 

The paper doesn’t mention that with changing times, more people will have data from actometers of one sort or another. These in theory could provide a baseline against which current activity levels might be compared.

 

Yeah.

I suspect the requirement of a 50% reduction one sometimes hears may not be appropriate, at least in a clinical setting (stricter criteria for research studies can be justified).

 

This is that the only table of data in the paper, apart from one giving demographic information:


It's interesting to see the relatively low numbers of (apparently) "healthy controls" who satisfied the Institute of Medicine criteria, and that the figures are lower than for the Canadian ME/CFS criteria.

It's also interesting to see how how much the Fukuda criteria depend on "substantial reduction in activity"; without them their specificity(s) is/are very bad, though might improve with the use of frequency and severity thresholds like those required with the Institute of Medicine criteria.