USA - NCHS/CDC Proposal for ICD-10-CM - adding SEID

[Colleen Steckel]

@anniekim @Colleen Steckel
Do you have any ideas how you will prevent that doctors diagnoze CFS instead of ME? I think, if there are two separate codes for CFS and ME that ME will be forgotten, too, unless there is education and advocacy. I think proposing two separate codes for CFS and ME should go hand in hand with proposing how this problem can be overcome.

(There is enough evidence for proposing two codes for ME and CFS, but there is also evidence for a proposal of adding SEID. I'm thinking - for those who don't want SEID added (me for example), there is evidence needed why adding it isn't backed up by science.)

For me it comes down to how patients are going to be treated depending on the diagnosis they are given. This may be a bit round about way of answering your question, but any answer I give is based on what the patients are going to get out of it.

I realize a lot of these discussions are academic exercises about how these criteria affect research. In the end - research that uses patients who match the patients who have ME as per the ICC is needed for ME-ICC patients to get answers. Experts who know what they are doing can use vague criteria and still get good answers for ME patients.

The problem comes when all these new researchers we are asking to join the field have no idea what an ME patient looks like and chooses those patients diagnosed with SEID who can easily travel to their facilities. (That is how ME patients have been weeded out of research for decades.)

In a perfect world what should happen if there are three different codes - is there would be three different treatment options based on which code is used. Unfortunately, we are hearing the medical education will be based on the IOM which means CFS and ME will fall to the wayside treatment wise.

Historically, specific requests to include information from either the CCC or ICC at the CDC was rebuffed. CFS and ME have had two different codes for a while now... and many of us have been able to get our doctors to use G93.3 (ME). This suggested change of moving CFS to the ME code section would undermine all the work we've done to get doctors to understand ME is NOT CFS. (Even IOM states they are two different conditions).

What makes no sense is the IOM specifically states there is no brain involvement for those who fit SEID and yet it is being put in the brain disorders category. I hear people describing the IOM using terms that is NOT what is verifiable in the actual document.

In my opinion, myths about what the IOM states have been left unchecked for so long that people don't actually know the IOM report does not say what people think it says. A quick look at the actual diagnostic algorithm clearly shows there is no neurological, immunological or cardiac involvement suggested. Therefore I have no expectations the CDC medical education will include anything about those aspects of the disease that is the most debilitating aspect of ME. Therefore SEID medical treatment recommendations are NOT going to be effective to those who have ME.

I have heard zero mention of ANY medical education for patients who have ME. In fact every effort to get the CDC to include medical information for us has been rejected.

So the answer - finally to your question. This is the exact same challenge we've been fighting for 30+ years. How to get medical education in the hands of doctors that actually applies to patients who have ME. The solution is same as what many experienced advocates have been asking for since 2013 - that US Health and Human Services adopt the ICC and educate using information based on the IC primer for those patients who fit the ICC.

No matter what disease we are talking about the 6 month waiting period must be abolished. Early intervention is the key to the best outcomes. The ICC is the only criteria that drops the six month waiting period.

 

[Hoopoe]

What makes no sense is the IOM specifically states there is no brain involvement for those who fit SEID and yet it is being put in the brain disorders category. I hear people describing the IOM using terms that is NOT what is verifiable in the actual document.

Where does it say this? I'm looking at it right now and it has a whole section on brain abnormalities.

In my opinion, myths about what the IOM states have been left unchecked for so long that people don't actually know the IOM report does not say what people think it says.

Please tell me more about these myths.

For example, what evidence of brain abnormalities did they omit? Can you name the abnormality, the article that first reported it, and any subsequent replications that give us confidence that it's a consistent finding in a particular group of patients?

 

[Jonathan Edwards]

How can SEID be in the ICD CM in other disorders of the nervous system when the IOM said SEID showed no brain inflammation?

A disorder of the nervous system does not have to have brain inflammation. There are lots of disorders of the nervous system without inflammation. Most of them have some other identifiable pathology but that is irrelevant. We know ME is a disorder of the nervous system because of the symptoms. That is all you need to put it in that category.

I have not yet come a cross a researcher planning to use SEID for research. Most want to stick to something like CCC.

 

[Jonathan Edwards]

IMO, one of the things the IOM did well for clinical diagnosis is to change from a diagnosis by exclusion to a positive diagnosis based on a recognition of hallmark symptoms such as PEM. This does not mean that doctors should not perform a solid differential diagnosis to look for alternative diagnoses that could explain the symptoms. They have to do that and they also need to identify co-morbid conditions.

That was very much my feeling.

 

[Barry]

We know ME is a disorder of the nervous system because of the symptoms.

Could you elaborate on that please. What symptoms are the ones that pin it down to a disorder of the nervous system?

 

[Jonathan Edwards]

Could you elaborate on that please. What symptoms are the ones that pin it down to a disorder of the nervous system?

Cognitive dysfunction, sensitivity to light and sound principally.

Being a disorder of the nervous system does not exclude qualifying for another category. MS is a disorder of the nervous system and an immunological disorder for instance.
One could argue that it is not clear that anatomically ME is limited to the nervous system so should be called multi-system but as things are the nervous system is the one anatomical domain we can be sure is affected and it is reasonably plausible that it is the only one. So disease of the nervous system would be entirely appropriate. These categories are pragmatic at the best of times.

 

[Colleen Steckel]

Where does it say this? I'm looking at it right now and it has a whole section on brain abnormalities.

Thank you for asking for clarification.

Cognition issues are definitely covered. But the outcome of that information lands us right back in cognitive behavior therapy. Cognition issues can stem from many things.. like alcohol abuse - lack of sleep - etc. The take I'm getting from the cognition section (and what I fear doctors will take from it who are looking to have their preconceived notion that we just need behavioral therapy) is reinforced in this quote from the report.

"Another study found that cognitive-behavioral therapy for ME/CFS patients increased prefrontal cortical volume after 16 sessions, suggesting that changes in brain volume and structure associated with the illness may be reversible with treatment "

So what I'm reading in the IOM is more about cognition issues than brain disorders. I don't believe those are the same.

The conclusion from the report does not indicate any kind of actual brain abnormalities. Just slowed information processing issues.

"There is sufficient evidence that slowed information processing is common in patients with ME/CFS, and a growing body of evidence shows that it may play a central role in overall neurocognitive impairment associated with the disease. Such a deficit may be responsible for the disability that results in loss of employment and loss of functional capacity in social environments."

I'll need some time to come up with more information for your other question.

In the meantime - this is the kind of brain information seen in ME patients that confirms the brain itself is affected. This is not the kind of brain information I see in the IOM:

A brain MRI study of CFS: evidence of brainstem dysfunction and altered homeostasis. NMr Biomed 2011. www.ncbi.nlm.nih.gov/pubmed/21560176

Functional neuroimaging correlates of mental fatigue induced by cognition among CFS patients and controls. Neuroimage 2007. www.ncbi.nlm.nih.gov/pubmed/17408973

EEG source analysis of CFS. 2010 www.sciencedirect.com/science/article/pii/S0925492709002406

Patients with CFS have reduced absolute cortical blood flow. Clin Physiol Funct Imaging 2006. www.ncbi.nlm.nih.gov/pubmed/16494597

Cerebral blood flow is reduced in CFS as assessed by arterial spin labeling. J Neurol Sci. 2011. www.ncbi.nlm.nih.gov/pubmed/21167506

Brainstem perfusion is impaired in CFS. QJM 1995. www.ncbi.nlm.nih.gov/pubmed/8542261

Neuroimaging in CFS. 1998; www.amjmed.com/article/S0002-9343(98)00175-2/pdf

Regional grey and white matter volumetric changes in ME (CFS): a voxel-based morphometry 3 T MRI study. Br J Radiol 2012. www.ncbi.nlm.nih.gov/pmc/articles/PMC3474083/

Gray matter volume reduction in CFS. NeuroImage 2005. www.sciencedirect.com/science/article/pii/S1053811905001394

Brain positron emission tomography (PET) in CFS. Amer J Med 1998. www.ncbi.nlm.nih.gov/pubmed/9790483

Study of Cerebral Perfusion by NeuroSPECT in Patients with Chronic Fatigue Syndrome. In: Hyde BM, Goldstein J, Levine P, eds. The Clinical and Scientific Basis of Myalgic Encephalomyelitis, Chronic Fatigue Syndrome. 1992: 432-8.

The assessment of vascular abnormalities in late life CFS by brain SPECT: Comparison with late life major depressive disorder. J CFS 1995. www.tandfonline.com/doi/abs/10.1300/J092v01n01_05

Evidence for and pathophysiologic implications of hypothalamic-pituitary-adrenal axis dysregulation in fibromyalgia and CFS. Ann NY Acad Sci 1998. www.ncbi.nlm.nih.gov/pubmed/9629295

Altered central nervous system signal during motor performance in CFS. Clin Neurophysiol. 2004. www.ncbi.nlm.nih.gov/pubmed/15351380

Alterations of spatial-temporal parameters of gait in CFS patients. 1998. www.jns-journal.com/article/S0022-510X(97)00200-1/fulltext

Distinct cerebrospinal fluid proteomes differentiate post-treatment lyme disease from CFS. PLoS ONE 2011. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0017287

Spinal fluid abnormalities in patients with CFS. Clin Diagn Lab Immunol 2005. www.ncbi.nlm.nih.gov/pmc/articles/PMC540195/

Ventricular cerebrospinal fluid lactate is increased in CFS compared with generalized anxiety disorder: an in vivo 3.0 T (1)H MRS imaging study. NMR Biomed 2009. www.ncbi.nlm.nih.gov/pubmed/18942064

Hyperintense sensorimotor T1 spin echo MRI is associated with brainstem abnormality in CFS. www.sciencedirect.com/science/article/pii/S2213158218302237

Neuroinflammation in patients with CFS/ME: An ¹¹C-(R)-PK11195 PET Study. 2014. www.ncbi.nlm.nih.gov/pubmed/24665088

EEG characteristics in patients with CFS. (Abnormal changes in cerebral functions localized at the right frontal and left occipital) 2016. www.ncbi.nlm.nih.gov/pmc/articles/PMC4734796/

Grey and white matter differences in CFS – A voxel-based morphometry study. 2018. www.ncbi.nlm.nih.gov/pmc/articles/PMC5633338/

 

[Colleen Steckel]

Could you elaborate on that please. What symptoms are the ones that pin it down to a disorder of the nervous system?

I believe some of what you are looking for will be found in the post I just did that includes a number of studies involving the brain in ME patients.

 

[Medfeb]

CFS and ME have had two different codes for a while now... and many of us have been able to get our doctors to use G93.3 (ME).

Just to clarify... the only country in which CFS and ME have two different codes is the US. Every other country follows the World Health Organization, which classified both CFS and ME at G93.3 where they share the same code as the lead term "post-viral fatigue syndrome."

The ICD-10-CM proposal for the ICD-10-CM calls for CFS and ME to still have separate codes - G93.32 for ME and G93.33 for CFS in Option 2 - in order to keep them separate. If your doctor agreed to diagnose ME, he/she will still be able to do so by using the code G93.32.

 

[Jonathan Edwards]

None of the brain studies we have so far has been satisfactorily replicated and a number of them are pointing in opposite directions (reduced blood flow vs cell activation for instance). Even if one took all these studies at face value it would be impossible to make any consistent sense of what they mean. Clinical medicine directed at service provision has to be based on data that have been confirmed and validated in a way we just do not have for ME.

It is not as if the research community themselves believe we have useful data. I know Dr Campos Costa, Jim Baraniuk, Jonas Bergquist and so on. I don;t think any of them would claim we have hard data on neuropathology.

 

[Colleen Steckel]

Just to clarify... the only country in which CFS and ME have two different codes is the US. Every other country follows the World Health Organization, which classified both CFS and ME at G93.3 where they share the same code as the lead term "post-viral fatigue syndrome."

The ICD-10-CM proposal for the ICD-10-CM calls for CFS and ME to still have separate codes - G93.32 for ME and G93.33 for CFS in Option 2 - in order to keep them separate. If your doctor agreed to diagnose ME, he/she will still be able to do so by using the code G93.32.

You are correct. This issue of the ICD code is specific to the United States. Therefore the concerns are specifically for how the US doctors will be responding to patients.

Yes... a doctor "could" use G93.32 if he was educated to do that and there was a diagnostic criteria in the US that had been adopted to go with that. But I don't expect the US CDC to do that because they have repeatedly refused to do so. Currently the ONLY diagnostic information available for doctors in the US is what is on the CDC website. And that diagnosis is based on SEID.

Therefore the expectation of experienced advocates who have raised the alarm about this proposal is that doctors will switch everyone to the CDC recommended code of SEID and the treatments will be based on that information - basically behavioral modification - no testing or treatments for immune, cardiac, or neurological abnormalities.

 

[JaimeS]

I think you would need education. But I think this won't happen.

I will say that there are NUMEROUS med ed initiatives underway from every organization I can think of off the top of my head. There is a significant push for this.

 

[Medfeb]

Therefore the expectation of experienced advocates who have raised the alarm about this proposal is that doctors will switch everyone to the CDC recommended code of SEID...

Just to clarify... The CDC ME/CFS website does not recommend a specific ICD code and it does not use the term "SEID." It has used the term "ME/CFS" since it rolled out the IOM criteria.

 

[Hoopoe]

So what I'm reading in the IOM is more about cognition issues than brain disorders. I don't believe those are the same.

But is it true to say that "the IOM specifically states there is no brain involvement for those who fit SEID"?

In the meantime - this is the kind of brain information seen in ME patients that confirms the brain itself is affected. This is not the kind of brain information I see in the IOM:

A brain MRI study of CFS: evidence of brainstem dysfunction and altered homeostasis. NMr Biomed 2011. www.ncbi.nlm.nih.gov/pubmed/21560176

This study is included in the IOM report, which says: "Spin-echo magnetic resonance imaging (MRI) revealed midbrain white matter and gray matter volume changes in these patients at fatigue onset, which the authors found to be consistent with an insult to the midbrain affecting multiple feedback control loops (Barnden et al., 2011)."

I checked a few more studies that you listed (and which I avoided quoting for brevity) and many but not all of them are included. There could be other explanations for the omissions besides bias, such as these studies not being particularly interesting and the necessity to summarize (e.g. one omitted study was EEG in patients vs healthy controls, which I wouldn't consider particularly important). Are there any studies that are important yet missing?

The reason that the report doesn't attempt to define the illness in terms of specific brain, immune, cardiac, etc abnormalities is because there isn't sufficient evidence to do so. Many of these studies are small and unreplicated, and scientists don't consider them sufficient evidence (this is not bias against ME/CFS, it's just how things are done). It appears that you are interpreting this as a failure by the IOM report to acknowledge the reality of ME (because you're not familiar with reviewing and interpreting scientific evidence).

 

[Jonathan Edwards]

Dear @Colleen Steckel,

I am not sure I can put it better than @strategist does: It appears that you are interpreting this as a failure by the IOM report to acknowledge the reality of ME (because you're not familiar with reviewing and interpreting scientific evidence).

For a condition like rheumatoid arthritis there are thousands of papers like these, 95% of which get forgotten because they are not done well enough or never stand up to repetition. Of the studies you mention the only one that I would consider worth just keeping an eye out for replication of is the natriuretic peptide one. Most of the others lots of other people have tried to repeat and found nothing consistent.

I spent my life working on rheumatoid arthritis. I was lucky enough to make enough progress with understanding the disease to introduce a novel treatment (rituximab) for RA and a range of autoimmune diseases. I learnt to scrutinise research papers to see if they were well executed and whether they made any sense in terms of building an understanding.

I got interested in ME because I could see it was a degree more difficult than RA because there were no accepted pathological findings. There was nothing you could see down a microscope or on a biochemistry read out that you could build a theory around. What I did see was a scattered collection of researchers producing very unconvincing and mostly uninterpretable findings. Amongst that there were maybe half a dozen solid research groups who had done epidemiology or physiology studies - most of whom nobody had heard of. I thought it was worth trying to see whether I could contribute towards getting some real research going. I am not sure I have much to offer but I have tried because it all seems such a mess and PWME clearly need something better.

As far as I am aware there is no group of people with an illness called ME that includes demonstrable immunological abnormalities. Every normal healthy person has quirks of this or that level of antibodies or lymphocytes. That does not mean they have an immune disease. Moreover, there are plenty of labs that make money out of finding things wrong when there isn't. It is circular to say that the people with the immune tests out of line are the ones with ME because ME has immune tests out of line on criteria. We have no reason to think that there is any consistent immune abnormality that is part of the causation of any ME type illness. I realise that there are physicians who tell their patients this but I would call that miseducation rather than education.

We had much the same thing for RA in a slightly different way. Vast numbers of researchers claimed that the illness was based on autoimmune T cells and that there must be an autoantigen in joints. They thought it must be true because it had been published in the Lancet! It did not make sense of the pathology anyway. When we worked out what was actually going on it was clear why these ideas made no sense. Unfortunately this sort of herd behaviour where researchers all follow the same dead end ideas has got much worse in the last twenty years with the proliferation of trash journals.

What PWME need is science that actually stands up to scrutiny. There is a degree of enthusiasm for that now but people need to be aware that there is still an awful lot of hot air being produced. And high profile researchers are very often not the ones who actually know what they are doing.

 

[Inara]

I will say that there are NUMEROUS med ed initiatives underway from every organization I can think of off the top of my head. There is a significant push for this.

Would you say that the "worry" that doctors will go on with diagnozing CFS instead of ME is unfounded in the sense that this problem is quite present and ME orgs are working on it?

@Colleen Steckel, did I understand correctly that it should be the patients that "enforce" a diagnosis of ME instead of CFS? (I ask because I fear I didn't understand it entirely.)

 

[anniekim]

A disorder of the nervous system does not have to have brain inflammation. There are lots of disorders of the nervous system without inflammation. Most of them have some other identifiable pathology but that is irrelevant. We know ME is a disorder of the nervous system because of the symptoms. That is all you need to put it in that category.

I have not yet come a cross a researcher planning to use SEID for research. Most want to stick to something like CCC.

Yes, that is true, so stand corrected on that. I need to check whether the IOM report said there was not sufficient evidence for definitively saying there was neurological involvement.

Bateman in the US I believe is giving one of the NIH consortia groups, the Jackson lab, her patients and she uses IOM criteria. I have seen her say a piece of research will be using IOM criteria. The OMF have research studies that now say patients will meet CCC and IOM SEID. Why not just CCC?

 

[anniekim]

How do you exclusion criteria proponents think that the combination of ME and depression should be handled? Should patients with ME be denied a diagnosis of ME because they're also depressed as result of having lost their job, identity, and other important things?

What's best for the patient: to be denied a diagnosis of ME because they're also depressed, or having to choose between one of the two diagnoses with potential loss of access to useful treatment, or to get a diagnosis for every condition they actually have?

ME criteria with exclusionary criteria do not mean that those with both depression and ME cannot ultimately get both diagnoses and treatment for both if they are unlucky to have both and of course both should be treated. The exclusion for depression is for those who suffer from primary clinical depression. Those people should first be treated for their depression. If that treatment doesn't work and their symptoms fit the ICC criteria, they would be considered as suffering from primary ME and secondary depression due to chronic illness, or they have both major depressive disorder and ME. It depends on the clinical judgement of the doctor whether a patient's symptoms are primarily the result of a depressive disorder or if the patient has ME and a reactive or co-morbid depressive disorder.

This is opposed to the IOM criteria misdiagnosing major depressive disorder (MDD) as SEID or considering a patient has co-morbid SEID because the symptoms of MDD overlap with the nonspecific SEID symptoms.For example, a recent study at the Sleep Center at Emory University School of Medicine, “Systemic exertion intolerance disease/chronic fatigue syndrome is common in sleep centre patients with hypersomnolence: A retrospective pilot study,” found 21% of 187 patients with hypersomnolence (excessive daytime sleepiness) met the criteria for SEID.

The study authors interpreted the results of the study to mean that SEID is a common co-morbidity in the hypersomnolent population. An alternate interpretation is that the SEID criteria do not distinguish between patients with a hypothesized exertion intolerance disease and those whose symptoms are associated with a more appropriate existing diagnosis.

Research by Leonard Jason's group found 27% of a group diagnosed with MDD met the SEID criteria. 47% of group with a severe form of depression, melancholic depression, met the SEID criteria.
I have seen some claim that Jason’s description of PEM in his papers on SEID s different to the PEM in the IOM. Yet in the box for the IOM Guide for Clinicians, which is what doctors will actually use, the SEID criteria just says post exertional malaise and asterisked next to it to add “frequency and severity of symptoms should be assessed. The diagnosis of ME/CFS (SEID) should be questioned if patients do not have these symptoms at least half of the time with moderate, substantial, or severe intensity”.
If doctors read the full SEID clinical guide it says PEM is worsening of a patient’s symptoms and function after exposure to physical or cognitive stressors that were normally tolerated before disease onset.
The CDC CFS Toolkit for years defined PEM as "Postexertional malaise (extreme, prolonged exhaustion and sickness following physical or mental activity). The term "malaise" has been used by doctors for years to describe a vague feeling of discomfort reported by patients.

Jason defines PEM in his SEID research as, "To meet the post-exertional malaise criteria, a patient would need to have indicated presence of at least 1 of our two post-exertional malaise symptoms: sickness/fatigue for >24 h after exercising or experiencing high levels of fatigue after everyday activity." This is consistent with the vague CDC definition of PEM. Jason is a careful researcher of case definitions relying on self-reported symptoms.

The meaning of such subjective terms as "profound, prolonged, moderate, substantial, or severe intensity" are open to a variety of interpretations. The IOM criteria allow PEM of "moderate intensity" to be used for diagnosis.

If the IOM report wanted the symptom of PEM to mean something unique to SEID and more specific, they should have used a different term than the Fukuda term PEM, which had already been defined as stated above and is nonspecific, being commonly reported in many medical and psychiatric conditions.

 

[anniekim]

The concern that IOM criteria would lead to diluted research cohorts and thus lack of progress is potentially valid, but rests on the assumption that we already have a pretty good idea of what the illness looks like. Yet if the underlying assumption is incorrect, it could also lead to lack of progress.

It appears there is one side taking the position that we already have a pretty good idea of what ME is and another side taking the position that we still need to discover what the illness is. We don't know what the problem at the root of the illness actually is, and we have no real biomarker. It is the second side that is on solid ground.

If the SEID criteria do end up being used as research criteria as history tells us may well happen the SEID criteria are not specific enough. Others on here believe that probably will not happen. I do not share that confidence and IOM criteria are already being used for research.

The ICC authors explain in their paper the importance of selecting as homogenous as possible patient cohorts for ME research and the problems that have risen by having too broad criteria for research these last few decades. They write:

“Research on ME: The logical way to advance science is to select a relatively homogeneous patient set that can be studied to identify biopathological mechanisms, biomarkers and disease process specific to that patient set, as well as comparing it to other patient sets. It is counterproductive to use inconsistent and overly inclusive criteria to glean insight into the pathophysiology of ME if up to 90% of the research patient sets may not meet its criteria (Jason 2009). Research on other fatiguing illnesses, such as cancer and multiple sclerosis (MS), is done on patients who have those diseases. There is a current, urgent need for ME research using patients who actually have ME.”

 

[adambeyoncelowe]

ME criteria with exclusionary criteria do not mean that those with both depression and ME cannot ultimately get both diagnoses and treatment for both if they are unlucky to have both and of course both should be treated. The exclusion for depression is for those who suffer from primary clinical depression. Those people should first be treated for their depression. If that treatment doesn't work and their symptoms fit the ICC criteria, they would be considered as suffering from primary ME and secondary depression due to chronic illness, or they have both major depressive disorder and ME. It depends on the clinical judgement of the doctor whether a patient's symptoms are primarily the result of a depressive disorder or if the patient has ME and a reactive or co-morbid depressive disorder.

This could be quite dangerous, actually. Some patients with ME respond very badly to SSRIs, which are frequently prescribed for MDD. So treating MDD without any consideration for ME, using the exclusion process you've suggested, could actually make some patients worse.

Besides, I don't think that's how practising clinicians use exclusion criteria anyway. They're guided by their clinical judgement more than anything, and use whichever labels fit the best. I think @Jonathan Edwards will be able to be more accurate here.

This is different to research, where you have to properly and much more thoroughly screen patients.

This is opposed to the IOM criteria misdiagnosing major depressive disorder (MDD) as SEID or considering a patient has co-morbid SEID because the symptoms of MDD overlap with the nonspecific SEID symptoms.For example, a recent study at the Sleep Center at Emory University School of Medicine, “Systemic exertion intolerance disease/chronic fatigue syndrome is common in sleep centre patients with hypersomnolence: A retrospective pilot study,” found 21% of 187 patients with hypersomnolence (excessive daytime sleepiness) met the criteria for SEID.

The study authors interpreted the results of the study to mean that SEID is a common co-morbidity in the hypersomnolent population. An alternate interpretation is that the SEID criteria do not distinguish between patients with a hypothesized exertion intolerance disease and those whose symptoms are associated with a more appropriate existing diagnosis.

Research by Leonard Jason's group found 27% of a group diagnosed with MDD met the SEID criteria. 47% of group with a severe form of depression, melancholic depression, met the SEID criteria.
I have seen some claim that Jason’s description of PEM in his papers on SEID s different to the PEM in the IOM. Yet in the box for the IOM Guide for Clinicians, which is what doctors will actually use, the SEID criteria just says post exertional malaise and asterisked next to it to add “frequency and severity of symptoms should be assessed. The diagnosis of ME/CFS (SEID) should be questioned if patients do not have these symptoms at least half of the time with moderate, substantial, or severe intensity”.
If doctors read the full SEID clinical guide it says PEM is worsening of a patient’s symptoms and function after exposure to physical or cognitive stressors that were normally tolerated before disease onset.
The CDC CFS Toolkit for years defined PEM as "Postexertional malaise (extreme, prolonged exhaustion and sickness following physical or mental activity). The term "malaise" has been used by doctors for years to describe a vague feeling of discomfort reported by patients.

Jason defines PEM in his SEID research as, "To meet the post-exertional malaise criteria, a patient would need to have indicated presence of at least 1 of our two post-exertional malaise symptoms: sickness/fatigue for >24 h after exercising or experiencing high levels of fatigue after everyday activity." This is consistent with the vague CDC definition of PEM. Jason is a careful researcher of case definitions relying on self-reported symptoms.

The meaning of such subjective terms as "profound, prolonged, moderate, substantial, or severe intensity" are open to a variety of interpretations. The IOM criteria allow PEM of "moderate intensity" to be used for diagnosis.

If the IOM report wanted the symptom of PEM to mean something unique to SEID and more specific, they should have used a different term than the Fukuda term PEM, which had already been defined as stated above and is nonspecific, being commonly reported in many medical and psychiatric conditions.

You've stated the problem with these studies yourself: they use limp interpretations of PEM (as post-exertional fatigue). They're using their own interpretation of what they think the report says, rather than what the report actually says. Jason certainly knows better than this, so I treat his results with suspicion.

The IOM is also more specific than this. In fact, it specifically says it's more than 'fatigue following a stressor':

PEM is an exacerbation of some or all of an individual’s ME/CFS symptoms that occurs after physical or cognitive exertion and leads to a reduction in functional ability (Carruthers et al., 2003). As described by patients and supported by research, PEM is more than fatigue following a stressor. Patients may describe it as a post-exertional “crash,” “exhaustion,” “flare-up,” “collapse,” “debility,” or “setback.”2 PEM exacerbates a patient’s baseline symptoms and, in addition to fatigue and functional impairment (Peterson et al., 1994), may result in flu-like symptoms (e.g., sore throat, tender lymph nodes, feverishness) (VanNess et al., 2010); pain (e.g., headaches, generalized muscle/joint aches) (Meeus et al., 2014; Van Oosterwijck et al., 2010); cognitive dysfunction (e.g., difficulty with comprehension, impaired short-term memory, prolonged processing time) (LaManca et al., 1998; Ocon et al., 2012; VanNess et al., 2010); nausea/gastrointestinal discomfort; weakness/instability; lightheadedness/vertigo; sensory changes (e.g., tingling skin, increased sensitivity to noise) (VanNess et al., 2010); depression/anxiety; sleep disturbances (e.g., trouble falling or staying asleep, hypersomnia, unrefreshing sleep) (Davenport et al., 2011a); and difficulty recovering capacity after physical exertion (Davenport et al., 2011a,b). In some cases, patients experience new symptoms as part of the PEM response.

The IOM report also suggests that objective measures such as the two-day CPET be used. It also quotes Jason's earlier studies (e.g., Jason et al., 1999, 2004, 2014) to make the case for what PEM is, so for Jason not to use his own stricter definitions when they're mentioned in the report suggests to me that he wants the criteria to fail in his trials.

Honestly, there are people saying things about the IOM that are patently untrue, and yet they're accusing others of not understanding what the report means!