Two symptoms can accurately identify post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome 2023 Davenport et al

BACKGROUND:
Post-exertional malaise (PEM) is the hallmark symptom of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) yet its diverse manifestations make it difficult to recognize. Brief instruments for detecting PEM are critical for clinical and scientific progress.

OBJECTIVE:
To develop a clinical prediction rule for PEM.

METHOD:
49 ME/CFS and 10 healthy, sedentary subjects recruited from the community completed two maximal cardiopulmonary exercise tests (CPETs) separated by 24 hours. At five different times, subjects reported symptoms which were then classified into 19 categories. The frequency of symptom reports between groups at each time point was compared using Fisher’s exact test. Receiver operating characteristics (ROC) analysis with area under the curve calculation was used to determine the number of different types of symptom reports that were sufficient to differentiate between ME/CFS and sedentary groups. The optimal number of symptoms was determined where sensitivity and specificity of the types of symptom reports were balanced.

RESULTS:
At all timepoints, a maximum of two symptoms was optimal to determine differences between groups. Only one symptom was necessary to optimally differentiate between groups at one week following the second CPET. Fatigue, cognitive dysfunction, lack of positive feelings/mood and decrease in function were consistent predictors of ME/CFS group membership across timepoints.

CONCLUSION:
Inquiring about post-exertional cognitive dysfunction, decline in function, and lack of positive feelings/mood may help identify PEM quickly and accurately. These findings should be validated with a larger sample of patients.

Open access, https://content.iospress.com/articles/work/wor220554

 

"Inquiring about post-exertional cognitive dysfunction" may well not identify everyone who is suffering from post-exertional cognitive dysfunction, as they might not even understand questions!

I haven't read the whole thing, so maybe there is some way to compensate for this.

 

Lack of positive mood is interesting. Often I enjoy doing stuff that gives me PEM. If I exercise I feel quite good during the PEM delay. Once I get PEM, there's a modest tendency to be in a moderate or bad mood. If PEM affects our moods, why? Is it the effect of PEM on the brain, simply because PEM is disappointing, or is this even a useful question to ask?

Cognitive dysfunction and loss of function are the most crucial elements of PEM to me. I feel quite tired, but everyone experiences fatigue to some degree. But ordinary activities depleting your energy to the point of confusion or debilitation is unique to ME.

 

The immediate problem I see is that these factors are all unmeasurable; they depend on personal judgement. I don't see it being all that much more reliable than just asking people whether they consistently feel worse after their usual triggers.

Isn't there a significant risk of harm to PWME from CPETs? How many people might go from moderate to long-term severe while doing this study? "First do no harm!"

 

Twitter thread by Todd Davenport talking about this paper:

 

PEM affects gut here ( motility slows, food intake decreases but can have acute carb craving due to low energy state )
Gut key to providing basis for neurotransmitter functionality ?