Post-Exertional Malaise (PEM) in ME/CFS: what do patients say about it?

"The findings of this survey suggest that there are key domains of this symptom, including triggers, symptom onset, and duration, which have often not been comprehensively assessed in a previous PEM [post-exertional malaise] instrument."

So said the findings reported by Carly Holtzman and colleagues [1] (open-access available here) examining (yet again and yet again) an important part of the clinical profile of the conditions known as myalgic encephalomyelitis (ME) / chronic fatigue syndrome (CFS): post-exertional malaise or PEM.

Although still the source of some debate (see here), PEM basically refers to "a worsening of ME/CFS symptoms after minimal physical or mental exertion." Some authors have used other words to describe PEM - "payback" is one of them - but the sentiments remain the same: a physiological (and psychological) 'cost' following exertion. And said exertion does not necessarily have to be over-exertion either.

In light of the 'confusion' around PEM, Holtzman et al decided on a rather sensible course of action: "to try to develop a comprehensive measure [of PEM] with active collaboration of the patient community." This follows other independent research that has reaped the rewards of asking patients suffering with ME/CFS (yes, suffering) about their experience of their illness (see here for example). To do this, one of the rather famous authors on the Holtzman paper - Leonard Jason - started some conversations with various other patients who were unhappy with some of the descriptions of PEM that were being bounced around. Joined by Holtzman, things took off with regards to a questionnaire that was developed with PEM in mind [2] as we are told that: "comments and items received helped shape each new revision of the questionnaire."

"A survey was ultimately developed and was subsequently completed by 1534 members of the patient community."

Findings? Well, first and foremost "94.4% reported being diagnosed by a medical doctor." Nearly three-quarters of participants reported 'symptom exacerbation' immediately following exertion. Nine out of ten participants "had experienced delayed onset after exertion." As to the triggers of PEM, well, "basic activities of daily living" was a big one, as was "emotional events (88.3%), noise (85.5%), and sensory overload (83.6%)." What sorts of symptoms were experienced? So: "reduced stamina and/or functional capacity (99.4%), physical fatigue (98.9%), cognitive exhaustion (97.4%), problems thinking (97.4%), unrefreshing sleep (95.0%), muscle pain (87.9%), insomnia (87.3%), muscle weakness/instability (87.3%), temperature dysregulation (86.9%), and flu-like symptoms (86.6%)." Quite a few. How long did PEM last for? An average of 3-6 days (that's days) and in some cases, an awful lot longer. Also: "67.1% of the sample had experienced a “crash” that never resolved." Most participants who answered the survey also felt that it pretty well reflected their experience of PEM.

There's quite a bit more to do in this area in terms of developing said questionnaire and hopefully putting more flesh on the descriptive bones of PEM. I'm also inclined to suggest that as well as describing PEM and how it is experienced by those diagnosed with ME/CFS, science needs to do a lot more on the biology of PEM and what could potentially help (yet again, minus the psychobabble). Still, 'asking patients' continues to be an important theme in ME/CFS research...

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[1] Holtzman CS. et al. Assessment of Post-Exertional Malaise (PEM) in Patients with Myalgic Encephalomyelitis (ME) and Chronic Fatigue Syndrome (CFS): A Patient-Driven Survey. Diagnostics (Basel). 2019 Mar 2;9(1). pii: E26.

[2] Jason LA. et al. The development of an instrument to assess post-exertional malaise in patients with myalgic encephalomyelitis and chronic fatigue syndrome. J Health Psychol. 2018 Oct 24:1359105318805819.

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What nearly 1500 patients with ME/CFS actually think about CBT, GET and pacing therapy

Today I'm discussing the findings reported by Keith Geraghty and colleagues [1] (open-access might be available here).

Looking at some interesting data derived from a rather large patient survey, authors examined what people diagnosed with myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) actually thought about / experienced when it came to three intervention options: cognitive behavioural therapy (CBT), graded exercise therapy (GET) and pacing therapy (PT). A little bit of context about these interventions can be seen here including reference to some other peer-reviewed published work from members of this authorship group.

Based on the results of a survey offered by one of the premier UK organisations devoted to ME/CFS - certainly the one I tend to use when it comes to defining the spectrum that is ME/CFS - Geraghty et al add something to a body of research looking at the 'real world' impact (or not) of the various interventions currently advised for 'treating' CFS/ME (at least here in the UK). Their analyses suggested that: "While a small percentage of patients report some benefit from either CBT or GET, the majority experience no benefit." Even worse: "GET brings about a substantive deterioration in symptoms for almost half of patients"; something important to mention in the context of other, similar, intervention results being published earlier this year (see here).

At this point, I'll also refer you to other discussions of the Geraghty paper (see here).

Details are important to the Geraghty results. Including quite a sizeable cohort (N=1428) and asking over 200 questions "regarding treatment, particularly CBT, GET or PT", results were also compared against other patient survey results in the context of the intervention(s) being scrutinised. The combined results painted a similar sort of picture when it comes to experiences of the interventions insofar as "CBT brought about improvement in symptoms for approximately 35 per cent of respondents (65% unchanged/worse)" and "25 per cent of GET reported improvement in symptoms (17% unchanged/54% worse)." All this needs to be read in the context of the primary medical tenet: first, do not harm.

Geraghty et al acknowledge that there are limitations to their study results; not least that recall bias might be a potentially important issue and also that delivery of said interventions  might not have been carried out in "a uniform manner" (something also mentioned in the paper by Collin & Crawley [2]). With all due respect to the respondents, I might also add that independent confirmation of their diagnosis - knowing how important this - might also have provided some further methodological strength to the results too.

But in the context that patient surveys "offer a valuable insight into the ‘patient experience’" and how controversial some (all?) of these intervention options have been/continue to be in relation to CFS/ME (see here), these latest results represent an important research voice. They suggest yet again, that blanket recommendations for treating CFS/ME may have lots of potential effects (some positive but also quite a few negative) for many, many people diagnosed with such debilitating conditions. And once again, in the words of Jonathan Edwards [3] "If they [those diagnosed with ME/CFS] are still ill, presumably these approaches have failed and the priority is to find something more effective." Indeed (but don't hold your breath at least here in Blighty).

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[1] Geraghty K. et al. Myalgic encephalomyelitis/chronic fatigue syndrome patients' reports of symptom changes following cognitive behavioural therapy, graded exercise therapy and pacing treatments: Analysis of a primary survey compared with secondary surveys. J Health Psychol. 2017 Aug 1:1359105317726152.

[2] Collin SM. & Crawley E. Specialist treatment of chronic fatigue syndrome/ME: a cohort study among adult patients in England. BMC Health Serv Res. 2017 Jul 14;17(1):488.

[3] Edwards J. PACE team response shows a disregard for the principles of science. J Health Psychol. 2017 Aug;22(9):1155-1158.

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