Two symptoms can accurately identify post-exertional malaise in ME/CFS

Experienced researchers into PEM at the Workwell Institute in California set out to find a way of diagnosing PEM and believe they have uncovered important clues that they now need to test further.

“Post-exertional malaise may manifest in a multitude of ways with different symptoms, timing, and intensity. Yet, the findings of this study indicate clinicians only need to focus on the presence and duration of just a few symptom categories and prolonged duration to identify its existence.”

Summary of symptom clusters at each time point during the study, which differentiated between people with ME/CFS and sedentary control subjects.

“Inquiring about post-exertional cognitive dysfunction, decline in function, and lack of positive feelings/mood may help identify PEM quickly and accurately.”

Two symptoms can accurately identify post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome, by Todd E Davenport, Lily Chu, Staci Stevens, Jared Stevens, Christopher Snell, Mark Van Ness, in Work, pp. 1-15, 2023 [DOI: 10.3233/WOR-220554

Research abstract:

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.