The Role of ME/CFS Phenotype in Outpatient Post-COVID Rehabilitation 2026 Kaiserseder et al

[Andy]

Post-COVID-19 syndrome (PCS) shares core clinical features with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), particularly persistent fatigue and post-exertional malaise (PEM). However, the prevalence of ME/CFS among PCS rehabilitation outpatients remains unclear.

Medical records of 216 PCS rehabilitation outpatients (57% female; age 47.7±12.5; January 2021 to April 2022) were retrospectively reviewed. During rehabilitation and at a six-month telephone follow-up, ME/CFS was diagnosed using the Canadian Consensus Criteria (CCC). Demographics, body mass index (BMI), FAS, and 6MWT were compared between phenotype and non-phenotype groups using logistic regression, repeated measures ANOVA, and chi-square tests (α=0.05).

Of 216 patients, 15 (93% female; age 40.6±10.7; BMI 25.7±5.6) met ME/CFS criteria, yielding a prevalence of 6.9%. Compared with non-ME/CFS phenotype, ME/CFS phenotype patients were significantly younger (p=0.01) and predominantly female (p=0.003). Baseline FAS was significantly higher (35.8±6.4 vs. 27.8±8.6, p=0.001) and did not improve (Δ +1.3±4.5 vs. Δ -5.1±6.2, p<0.001). Baseline 6MWT was significantly lower (479±132 m vs. 540±96.1 m, p=0.02) and both groups improved over time, but between-group change was not significant (p=0.49).

Approximately 7% of PCS in outpatient rehabilitation exhibit ME/CFS, characterized by severe, persistent fatigue, female predominance, and attenuated functional gains. While the FAS is a practical screening tool, confirmation via CCC remains essential. Future studies should validate these findings and explore tailored rehabilitation strategies for patients with ME/CFS.

Open access (in German)

 

[Evergreen]

Baseline FAS was significantly higher (35.8±6.4 vs. 27.8±8.6, p=0.001) and did not improve (Δ +1.3±4.5 vs. Δ -5.1±6.2, p<0.001).

FAS = Fatigue Assessment Scale

 

[Evergreen]

The figures are worth a look.
The fatigue figure (blue is fatigue pre-rehab, green is fatigue after rehab, left two columns are the group without ME/CFS, next two columns are the group with ME/CFS):

That's "Course/progression of fatigue on the FAS pre- and post-outpatient rehabilitation in groups with and without ME/CFS"

 

[Evergreen]

The 6 minute walking test figure:
(blue is pre-rehab, green is after rehab, left two columns are the group without ME/CFS, next two columns are the group with ME/CFS)

That's "Change in 6MWT in metres between the beginning and end of out-patient rehab in the group with and without ME/CFS"

 

[Simon M]

The 6 minute walking test figure:
(blue is pre-rehab, green is after rehab, left two columns are the group without ME/CFS, next two columns are the group with ME/CFS)
View attachment 31538
That's "Change in 6MWT in metres between the beginning and end of out-patient rehab in the group with and without ME/CFS"

The Cohens D for the mean difference for the six minute walking test for the grade exercise group in the Pace trial was 0.2. And not significant for the CBT group. This looks better than that, but I don't know what the Cohen's D would be here. But the result is very different from the effect on FAS..

 

[Evergreen]

The Cohens D for the mean difference for the six minute walking test for the grade exercise group in the Pace trial was 0.2. And not significant for the CBT group. This looks better than that, but I don't know what the Cohen's D would be here. But the result is very different from the effect on FAS..

Yeah, they end up a little more tired.

Dropouts are interesting too:
4.5% of those without ME/CFS dropped out vs 26.7% of those with ME/CFS (all of the latter due to "CRASHES").

I cannot see a description of the rehab content. But all ME/CFS patients reported consistent pacing as the most important strategy.

 

[Simon M]

Dropouts are interesting too:
4.5% of those without ME/CFS dropped out vs 26.7% of those with ME/CFS (all of the latter due to "CRASHES").

That is telling. I don't suppose they have a sensitivity analysis that assumes that those who dropped out declined rather than stay the same as baseline?

One of the laws of the Pace trial was that things he reported deterioration were assessed by "independent" medics (presumably independent of the study, not necessarily of the psychosocial perspective) and all were deemed to be unrelated to the therapies. What would've been very interesting was to have the reasons patients attributed their decline to, as in thus study. (That said, dropout rates were pretty low, much lower than in some earlier CBT/get trials that also reported spectacular results.)

 

[rvallee]

Future studies should validate these findings and explore tailored rehabilitation strategies for patients with ME/CFS.

Ah well here's your problem: you're supposed to do that before you claim the patients. The reverse question is far more meaningful: what is the role of rehabilitation in ME/CFS? None. What is this nonsense? And what they do even mean by "validate these findings"? What findings? This:?

and did not improve

Or that?:

between-group change was not significant

Which actually makes a case that even non-ME/CFS don't really benefit from any of this.

They keep finding that none of this serves any purpose and they can't stop doing it, there is no leadership, no strategy, no thinking involved.

 

[Evergreen]

I don't suppose they have a sensitivity analysis that assumes that those who dropped out declined rather than stay the same as baseline?

Alas, no.

They have a figure that compares different studies' estimates of prevalence that you might enjoy, though.

One of the laws of the Pace trial was that things he reported deterioration were assessed by "independent" medics (presumably independent of the study, not necessarily of the psychosocial perspective) and all were deemed to be unrelated to the therapies. What would've been very interesting was to have the reasons patients attributed their decline to, as in thus study. (That said, dropout rates were pretty low, much lower than in some earlier CBT/get trials that also reported spectacular results.)

I think those attributions would have been affected by the, ahem, "education" they had been given.