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The Ambiguous Term “ME/CFS”: Why ME and CFS Cannot Be Combined

For International ME Awareness Day, May 12, 2017

“One of the saddest lessons of history is this: If we’ve been bamboozled long enough, we tend to reject any evidence of the bamboozle. We’re no longer interested in finding out the truth. The bamboozle has captured us. It’s simply too painful to acknowledge, even to ourselves, that we’ve been taken. Once you give a charlatan power over you, you almost never get it back.”

Carl Sagan, astronomer and writer (1934-1996)

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Increasingly, researchers, doctors, advocates, and patients are using the mixed term “ME/CFS” as if it had some clear, specific meaning and referred to some identifiable disease. In actuality, however, the mixed term “ME/CFS” is ambiguous, logically incoherent, and a major impediment for making progress in research of the neurological disease Myalgic Encephalomyelitis, ME, ICD G93.3.

Additionally, patients diagnosed with chronic fatigue syndrome, CFS, and not meeting the more specific diagnostic criteria for ME, are also adversely affected by the use of the mixed “ME/CFS” term in research. Non-ME CFS while combined with ME under a single term cannot rationally be researched to identify other coherent patient groups, which could then be renamed and removed from the more encompassing CFS group. This rational strategy for resolving the current impasse in research was called for in the 2011 ME International Consensus Criteria paper, published in the Journal of Internal Medicine, and the 2012 International Consensus Primer, based on the ME-ICC.

The IC Primer states:

“The purpose of diagnosis is to provide clarity. The criterial symptoms, such as the distinctive abnormal responses to exertion can differentiate ME patients from those who are depressed or have other fatiguing conditions. Not only is it common sense to extricate ME patients from the assortment of conditions assembled under the CFS umbrella, it is compliant with the WHO classification rule that a disease cannot be classified under more than one rubric. The panel is not dismissing the broad components of fatiguing illnesses, but rather the ICC are a refinement of patient stratification. As other identifiable patient sets are identified and supported by research, they would then be removed from the broad CFS/CF category.”

The 2012 IC Primer: MD, CM, FRCPC; - name-us.org

Patients can use this convenient guide, prepared by the MEadvocacy organization, to determine if they meet the IC criteria for ME.

Understanding the problems created by combining the two disparate terms ME and CFS together as a single mixed diagnosis “ME/CFS” requires an understanding of how the two terms originated.

Myalgic Encephalomyelitis

The term “encephalomyelitis” was used in a 1956 paper by Dr. A. Melvin Ramsay describing an outbreak of infectious disease at the London Royal Free Hospital in 1955, “Encephalomyelitis simulating poliomyelitis,” published in the Lancet. In the same May 26, 1956 issue of the Lancet, an editorial attributed to Dr. E.D.Acheson suggested use of the name “benign myalgic encephalomyelitis.”

Downloaded from http://pmj.bmj.com/ on December 8, 2017 - Published by group.bmj.com

“The objections to any but a purely descriptive name for a disorder without a known cause or established pathology are obvious. For this reason, the term “benign myalgic encephalomyelitis” may be acceptable. It in no way prejudices the argument for or against a single or related group of causal agents; and it does describe some of the striking features of a syndrome characterized by;

(1) symptoms and signs of damage to the brain and spinal chord, in a greater or lesser degree;

(2) protracted muscle pain with paresis [partial paralysis, muscle weakness] and cramp;

(3) emotional disturbances in convalescence;

(4) normal C.S.F.;

(5) involvement, in some variants, of the reticuloendothelial system [part of the immune response system];

(6) a protracted course with relapses in severe cases;

(7) a relatively benign [death was not immediate] outcome.

It remains to identify this syndrome more precisely; but we believe its characteristics are now sufficiently clear to differentiate it from poliomyelitis, epidemic myalgia, glandular fever, the forms of epidemic encephalitis already described, and, need it be said, hysteria.”

It is important to note that fatigue of any kind is NOT mentioned in this early description of ME, based on the systematic clinical observation of patients with related symptoms identified during outbreaks of disease.

Acheson, writing later in a 1959 paper based on clinical observations made during 14 related outbreaks of disease, again did not mention fatigue of any kind as a commonly observed or diagnostically useful symptom:

All the outbreaks shared the following characteristics:

(1) headache

(2) myalgia

(3) paresis [muscle weakness, partial paralysis]

(4) symptoms/signs other than paresis suggestive of damage to brain, spinal cord/peripheral nerves

(5) mental symptoms

(6) low or absent fever in most cases

(7) no mortality.

In addition:

(1) a higher attack frequency in women

(2) a predominantly normal cerebrospinal fluid

(3) relapses have occurred in almost all outbreaks.

In eleven of the fourteen epidemics symptoms which suggest activity of the disease have persisted for months or years in a few cases, and in eight instances there was an apparent predilection for the nursing or medical professions. Lymphadenopathy was a feature in four outbreaks.” http://www.name-us.org/DefintionsPages/DefinitionsArticles/Acheson1959.pdf

Neither does Dr. Melvin Ramsay in his 1986 case definition of ME mention fatigue of any kind:

“A syndrome initiated by a virus infection, commonly in the form of a respiratory or gastrointestinal illness with significant headache, malaise and dizziness sometimes accompanied by lymphadenopathy or rash. Insidious or more dramatic onsets following neurological, cardiac or endocrine disability are also recognised. Characteristic features include:

(1) A multisystem disease, primarily neurological with variable involvement of liver, cardiac and skeletal muscle, lymphoid and endocrine organs.

(2) Neurological disturbance – an unpredictable state of central nervous system exhaustion following mental or physical exertion which may be delayed and require several days for recovery; an unique neuro-endocrine profile which differs from depression in that the hypothalamic/pituitary/adrenal response to stress is deficient; dysfunction of the autonomic and sensory nervous systems; cognitive problems.

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(3) Musculo-skeletal dysfunction in a proportion of patients (related to sensory disturbance or to the late metabolic and auto immune effects of infection)

(4) A characteristically chronic relapsing course.”


In the last paper published by Ramsay in 1990, and with Dr. Elizabeth Dowsett, this was the ME research case definition they used:

“We adopted the following clinical criteria for investigation of ME: a syndrome commonly initiated by respiratory and/or gastro-intestinal infection but an insidious or more dramatic onset following neurological, cardiac or endocrine disability occurs. The pathognomonic features are: a complaint of general or local muscular fatigue following minimal exertion with prolonged recovery time; neurological disturbance, especially of cognitive, autonomic and sensory functions; variable involvement of cardiac and other systems; a prolonged relapsing course.” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2429637/

The symptom of post-exertional muscle fatigue used here is very different from the symptom of perceived general fatigue, the subjective feeling of tiredness, that is used as the basis for making a CFS diagnosis. Muscle fatigue can be objectively measured. Perceived, general fatigue can only be evaluated by psychometric questionnaires – an important distinction.

People with ME may experience episodes of profound fatigue, but many people with ME do not have a feeling of persistent, chronic fatigue. Dr. Elizabeth Dowsett said in a 1992 interview:

“One of the most striking features of ME is that the patient is not tired all the time! Extreme and sudden variability of energy levels both within and between episodes of illness differentiate this syndrome from other diseases associated with fatigue. One can only deplore the current fashion in the United States as well as the United Kingdom to redefine and rename a disability which has been clearly described in the literature for at least 100 years.”

“There is nothing to be said in favour of the American acronym CFIDS (chronic fatigue immune deficiency syndrome) with its connotation of a primary immune dysfunction. The term ‘chronic fatigue syndrome’ recently adopted in this country also is nonspecific and non-descriptive because most of the definition is based on a vast number of exclusions (some of which, for example, endocrine disturbance, are actually found in ME).”

“‘Post-viral fatigue syndrome’, another British name, describes one essential feature (the association of the illness with viral infection) but gives the impression that the infection was antecedent rather than, as we now know, persistent. I prefer to use the more specific term ‘myalgic encephalomyelitis’ as it emphasizes the essential encephalitic component of the illness, the muscle pain, and the close clinical and epidemiological similarity to poliomyelitis.”

Chronic Fatigue Syndrome

The term “chronic fatigue syndrome” was introduced in a 1988 US CDC paper in response to an outbreak of unidentified disease in the Lake Tahoe region of Nevada and California in the mid-80s that the CDC only superficially investigated. Although there was a large overlap of symptoms in the Tahoe outbreak with outbreaks of ME around the world, the 1988 Holmes paper redefined, not ME, but a “chronic Epstein-Barr virus syndrome,” also known as “chronic mononucleosis.” It should be noted that E.D. Acheson had differentiated ME from mononucleosis, or glandular fever as it is called in the UK, in 1956. http://www.ncf-net.org/patents/pdf/Holmes_Definition.pdf

Because reportedly researchers found insufficient evidence of EB virus, the Holmes paper renamed the purported EB virus syndrome “chronic fatigue syndrome” with 6 months of persistent fatigue being the only required symptom common to all cases – along with various combinations of “minor” criteria including 11 symptoms and three signs. Very significantly, the Holmes paper emphasized that CFS was “an operational concept designed for research purposes that physicians must recognize not necessarily as a single disease but as a syndrome – a complex of potentially related symptoms that tend to occur together – that may have several causes.”

As such, CFS was defined as a diagnosis of exclusion – meaning that any objectively confirmable condition or diagnosis that could produce similar symptoms was considered exclusionary for CFS research. At that time, ME was an established diagnosis that had been listed in the WHO ICD as a neurological disease since 1969, almost 20 years before the “operational concept” of CFS was created. Because of a significant overlap of symptoms, an ME diagnosis should have been listed as exclusionary for CFS, but it was not.

It should be remembered that the defining feature of Holmes CFS, 6 months of persistent fatigue, had never been a required or descriptive symptom of ME. Myalgic encephalomyelitis had always been characterized by neurological and muscular signs and symptoms “suggestive of damage to the brain, spinal cord or peripheral nerves.”

Prominent ME specialist Dr. Byron Hyde wrote this comment in 2006 about the 1988 Holmes definition of CFS:

“It is my opinion that the CDC 1988 definition of CFS describes a non-existing chimera based upon inexperienced individuals who lack any historical knowledge of this disease process. The CDC definition is not a disease process. It is (a) a partial mix of infectious mononucleosis /glandular fever, (b) a mix of some of the least important aspects of M.E. and (c) what amounts to a possibly unintended psychiatric slant to an epidemic and endemic disease process of major importance.” http://www.imet.ie/imet_documents/BYRON_HYDE_little_red_book.pdf

Despite 1988 Holmes CFS being a “non-existing chimera” and a research “operational concept” based on a diagnosis of exclusion that should have been considered mutually exclusive with ME, the Holmes criteria became used for diagnosis by US doctors, unfamiliar with ME, and applied to a significant number of patients who, undoubtably, would have been more appropriately diagnosed with ME.

To further confuse matters, “Chronic fatigue syndrome” was added in 1992 to the index volume of the WHO ICD referenced to “Benign myalgic encephalomyelitis” in the neurological section of the volume of coded terms. This reference has been used as “evidence” that the very different diagnostic criteria for ME and CFS identify the same disease. Obviously, there is no support for this claim in either the Holmes definition of CFS, the 1986 Ramsay definition of ME, or the detailed descriptions of ME in the published medical literature by ME specialists such as Drs. Acheson, Ramsay, Dowsett, and Hyde.

The claim, based on the 1992 index entry in the WHO ICD, for the identity of ME and CFS is further refuted by the classification of CFS as an “ill-defined condition,” rather than as a neurological disease, by the US government agency that created and defined CFS, the CDC. As such, the CDC’s position must be considered authoritative as to the nature and classification of CFS. In the US ICD-9-CM, in use until 2015 and controlled by the CDC, CFS was coded as 780.71 in the Symptoms, Signs, And Ill-Defined Conditions section under 780.7 Malaise and fatigue. An ICD index entry, of course, does not relieve any doctor of the responsibility of using appropriate ME criteria to diagnose ME, rather than the broad, less specific CFS criteria, not even intended to be used for diagnosis. In 1994, the CDC, in collaboration with controversial UK psychiatrists Michael Sharpe and Simon Wessely, greatly expanded the definition of CFS, with the still used Fukuda definition – further removing the “ill-defined condition” CFS from any identity with the neurological disease ME.

Again, the 1994 Fukuda CFS definition was not allegedly intended for use in diagnosis, but as a “research framework” to gather together groups of subjects “to search for illness patterns consistent with the chronic fatigue syndrome.” Twenty-three years later and after numerous CFS studies, no such distinct illness pattern has been found to make Fukuda CFS anything other than the same ill-defined condition it was when created in 1994.

It also is unclear how the broad Fukuda research definition came to be widely used as diagnostic criteria, almost without any modification or increase in specificity. Used for diagnosis, the Fukuda CFS criteria cannot be said to diagnose a single identifiable disease or condition, but rather a group of undifferentiated conditions without a common etiology.

All patients diagnosed with Fukuda CFS have only the symptom in 6 months of self-reported, unexplained chronic fatigue in common for certain. In addition to chronic fatigue, they must report at least four of eight other poorly described symptoms. This gives a total of 163 combinations of symptoms that now can be considered chronic fatigue syndrome.

As a “diagnosis of exclusion” CFS can never be classified as a neurological disease, as is ME, or, indeed, as any specific disease. The Fukuda paper states the presence of “any previously diagnosed medical condition whose resolution has not been documented beyond reasonable clinical doubt and whose continued activity may explain the chronic fatiguing illness” is considered exclusionary for a case of Fukuda CFS. Certainly, myalgic encephalomyelitis meets this requirement and should be considered a neurological disease exclusionary for a diagnosis of CFS.

A diagnosis of ME can be objectively confirmed by observable signs and testing according to classic descriptions of the disease in the medical literature and the 2011 ME-ICC. The ME-IC Primer lists over two dozen laboratory and imaging tests that can be used to confirm a case of ME. A diagnosis of ME, therefore, should be always be considered exclusionary for a CFS diagnosis. In other words, the mixed condition “ME/CFS” simply cannot rationally exist, by definition. Frank Twisk has recently made a detailed argument why ME and CFS should not be, and cannot be, combined as a single diagnosis in his 2016 paper “Replacing myalgic encephalomyelitis and chronic fatigue syndrome with systemic exertion intolerance disease is not the way forward.”

That ME and CFS are mutually exclusive diagnoses was also confirmed by the 2015 US ICD-10-CM that has respective Type 1 Excludes notes for each diagnosis. This means no single patient can properly be given both the R53.82 CFS and the G93.3 ME codes. A doctor must code an “ME/CFS” diagnosis as either ME or CFS, and not assign both diagnoses to the same patient, following US ICD good practice standards.

“Myalgic Encephalomyelitis / Chronic Fatigue Syndrome”

Although some doctors used the term “ME/CFS” earlier to refer to the collective group of patients diagnosed with either ME or CFS, the combined single diagnosis of “ME/CFS” was not formally defined until 2003. Despite the incompatibility of ME and CFS as defined, the 2003 Canadian Consensus Criteria (CCC) paper gives diagnostic criteria for a mixed condition “ME/CFS,” rather than either ME or CFS. However, because of the large overlap of Canadian “ME/CFS” symptoms with the symptoms of ME, most patients meeting the CCC are likely to have ME and meet the ME-ICC. http://www.name-us.org/DefintionsPa…

The choice of the term “ME/CFS” was based on the belief by the CCC authors that ME and CFS are “probably the same illness” and “the diagnosis of myalgic encephalomyelitis and chronic fatigue syndrome are generally used interchangeably in Canada.” However, the 12 CCC authors offered no references or argument to support this claim. Considering ME and CFS to be the same disease directly contradicts the descriptions of ME in the medical literature, and both the Holmes and Fukuda CFS definitions, discussed above.

It may indeed be true that the diagnoses ME and CFS are used interchangeably in Canada. However, it must be conceded that such interchangeable use is incorrect and contrary to the standard published definitions and descriptions ME and CFS in the medical literature. Generally, groups of professionals in a field uphold standards of clear and rational terminology. No group of zoologists, for example, would support calling the Texas horned lizard (Phrynosoma cornutum) a Texas horned lizard/toad because the terms “horned lizard”and “horned toad” are used interchangeably in the southwestern US.

However, with ME and CFS, groups of professionals are willing to support popular misuse of terms by using ME and CFS interchangeably themselves, or combining the two disparate terms together into the ambiguous combination “ME/CFS.” The 12 authors of the 2003 Canadian diagnostic criteria for “ME/CFS,” all but one from Canada and the US, could have avoided a great deal of subsequent confusion by calling the disease their criteria diagnose simply “myalgic encephalomyelitis,” rather than “ME/CFS,” and dropping the 6 months of unexplained chronic fatigue as a mandatory requirement for diagnosis. Essentially, this is what the expanded International Consensus Criteria panel with 26 members from 12 countries, also led by Dr. Bruce Carruthers, did in the 2011 ME-ICC.

It is unclear why any medical scientific group would support combining ME and CFS as a single diagnosis. To do so inevitably creates confusion and degrades the established diagnosis of ME. Combining a neurological disease with an ill-defined condition creates an ambiguous mixture that becomes yet another ill-defined condition, rather than a neurological disease. Canadian “ME/CFS” requires 6 months of unexplained chronic fatigue for diagnosis, which had never before been associated with classic ME in the medical literature. Also combining ME and CFS as a single diagnosis directly contradicts the long-standing definition of CFS as a diagnosis of exclusion by both the Holmes and Fukuda CDC papers.

By definition, it is logically incoherent to combine a diagnosis of exclusion, CFS, with an objectively confirmable diagnosis, such as ME, into a single self-contradictory term. The standard meaning of one part of the term contradicts the other. The term “ME/CFS,” therefore, is similar to such logically incoherent terms as a “round square” or “non-malignant cancer.” The mixed condition “ME/CFS” cannot rationally exist, by definition. Nevertheless, “ME/CFS” has become a widely used term, as if it could ever have some clear meaning. In practice, the term “ME/CFS” can mean ME, CFS, both, or neither – almost anything anyone wants it to mean.

Problems Created by Using the Mixed Term “ME/CFS” in Research

The problems created by using the ambiguous term “ME/CFS” in research can be shown, for example, in the recent 2017 Nagy-Szakal et al. study “Fecal metagenomic profiles in subgroups of patients with myalgic encephalomyelitis/chronic fatigue syndrome” co-authored by prominent researchers Ian Lipkin and Mady Hornig, along with well-known CFS doctors Lucinda Bateman, Nancy Klimas, Anthony Komaroff, Susan Levine, José Montoya, and Daniel Peterson. https://microbiomejournal.biomedcentral.com/…

Regardless of the merits of the sophisticated analysis of samples taken, it is unclear, in the first place, what disease or condition Nagy-Szakal et al. is studying. It is equally unclear to which specific patient group, or subgroup, the results of the study could be applied. The study used 50 “ME/CFS” labelled subjects “who met the 1994 CDC Fukuda and the 2003 Canadian consensus criteria for ME/CFS.” However, there is no Fukuda criteria for “ME/CFS,” only CFS.

No attempt was made in the study to evaluate any of the subjects for ME using the 2011 ME-ICC research criteria, as has been done in a number of significant studies in Australia and Japan.

This article, “Gene differences found in severe Myalgic Encephalomyelitis patients” has a link at the bottom to other Australian Griffith University studies using the ME-ICC. https://meaustralia.net/2016/09/08/gene-differences-found-in-severe-myalgic-encephalomyelitis-patients/

This is the Nakatomi et al. 2014 ME neuroinflammation study which used the ME-ICC. http://jnm.snmjournals.org/content/55/6/945.full

The multiple subject selection criteria used in the Nagy-Szakal et al. study has several basic problems. In the first place, the 2003 Canadian Consensus Criteria for “ME/CFS” are NOT research criteria and were intended by the authors only to be used by clinicians for diagnosis. This can readily be seen from the title of the Canadian criteria paper “Myalgic Encephalomyelitis / Chronic Fatigue Syndrome: "Clinical Working Case Definition, Diagnostic and Treatment Protocols.”

Additionally, the CCC authors make a clear distinction between their diagnostic definition and a research definition in the paper: “As the CDC [Fukuda CFS] definition was primarily created to standardize research, it may not be appropriate to use for clinical diagnoses, a purpose for which it was never intended. There has been a growing demand within the medical community for a clinical case definition for ME/CFS for the benefit of the family physician and other treating clinicians.” http://www.name-us.org/DefintionsPages/DefinitionsArticles/ConsensusDocumentFull.pdf

Unlike the Fukuda CFS criteria, the Canadian criteria have never been standardized for research – a purpose for which they were never intended – and their application, consequently, can vary from study to study. This makes the results of any research studies using the Canadian diagnostic criteria difficult, if not impossible, to compare or replicate. Without the ability to be replicated, any research study becomes a “one-off” with inconclusive and unreliable results.

The inclusion in the Canadian criteria of the requirement of 6 months of unexplained chronic fatigue, which was not a symptom previously associated with ME, as discussed above, makes it unclear what condition the Canadian criteria diagnose – although, in practice, it is most likely to be ME. The Canadian criteria’s mandatory 6 months of unexplained chronic fatigue in the is taken directly from the Fukuda CFS (not “ME/CFS”) requirements without explanation. There is, however, a large overlap of other Canadian criteria symptoms with ME symptoms when used for diagnosis.

On the other hand, if used for research, the Canadian criteria can produce an unrepresentative sample of ME patients, not all of whom may report experiencing sufficient chronic fatigue to meet either the Canadian or Fukuda criteria. Use of the Canadian criteria for research is likely to skew samples toward those subjects experiencing more fatigue and malaise, rather than subjects with the neurological and muscular symptoms found in ME. Also, the required delayed abnormal multi-system physiological response to exertion that is is found in ME is not adequately described by the term “malaise,” a vague feeling of discomfort or uneasiness, used in the Canadian criteria.

Any portion of Canadian criteria “ME/CFS” subjects who could also meet ME criteria could not additionally meet Fukuda research criteria, if all exclusions were applied. As the CDC stated in a 2010 paper:

“The 1994 International CFS case definition [Fukuda] and the Canadian Consensus Criteria are different and do not necessarily identify similar groups of ill persons. Most notably, the Canadian Criteria include multiple abnormal physical findings such as spatial instability, ataxia, muscle weakness and fasciculation, restless leg syndrome, and tender lymphadenopathy. The physical findings in persons meeting the Canadian definition may signal the presence of a neurologic condition considered exclusionary for CFS…”

Also the CDC has published on its CFS website that ME and CFS are different distinct diagnoses:

“The name myalgic encephalomyelitis (ME) was coined in the 1950s to clarify well-documented outbreaks of disease; however, ME is accompanied by neurologic and muscular signs and has a case definition distinct from that of CFS.”

It is unclear how an individual Nagy-Szakal et al. research subject could meet both the Canadian and Fukuda criteria. Either the subject somehow met the Canadian criteria without having ME, or met the Fukuda criteria without all exclusions being applied. Furthermore, it is unclear why researchers would want to use the less specific Fukuda criteria with the more specific Canadian criteria, in the first place. Meeting the Fukuda CFS criteria, in addition to the more specific Canadian criteria, would NOT mean the results of the study could be applied to the more diverse CFS patient group, diagnosed using only Fukuda. For example, once more specific criteria had been applied to a group of research subjects, also meeting the criteria for bipedalism would not mean the results of a study on these subjects could be applied to everyone with two feet.

The basic ambiguity of the term “ME/CFS” makes it unclear which of the Nagy-Szakal et al. subjects had ME, and which only met the less specific CFS criteria. However, none of the subjects in the study were evaluated for ME using research criteria for ME. Usually medical research on a disease uses subjects that have been carefully determined unequivocally to have that disease. As the IC Primer states:

“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.”

Using the ambiguous term “ME/CFS” to describe subjects who are claimed to have met two sets incompatible criteria, makes it is unclear what disease or condition Nagy-Szakal et al. studied. Because of use of unclear terminology, the results of this study can neither be clearly applied to people with ME, nor to some subgroup of those diagnosed with CFS. Nevertheless, the study goes on to suggest there are subgroups of “ME/CFS” without first clearly establishing what an “ME/CFS” group might be.

An even greater problem arises from the Nagy-Szakal et al. study authors’ misrepresentation of how “ME/CFS” is currently diagnosed. They state in the “Background” section of the paper that:

“Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is an unexplained, chronic debilitating disorder that in the USA alone is estimated to affect up to 2.5 million people, with annual costs of $24 billion [1, 2]. Diagnosis is based on the presence of three of the following symptoms: (1) fatigue impairing an individual’s ability to engage in occupational, educational, social, or personal activities for at least 6 months; (2) post-exertional malaise and unrefreshing sleep; and (3) at least one of the following two symptoms: cognitive impairment and orthostatic intolerance [1].”

Reference [1] is the 2015 IOM “ME/CFS” report. https://www.nap.edu/read/19012/chapter/1

It is difficult to understand why the experienced Nagy-Szakal et al. authors would mistakenly claim that “ME/CFS” is currently diagnosed using the untested IOM criteria, rather than the more specific 2003 Canadian diagnostic criteria in use for years. The 2015 IOM diagnostic criteria are not yet in use, and, if implemented, would diagnose a greatly expanded version of “ME/CFS,” that the IOM report wants to call a “systemic exertion intolerance disease,” or “SEID.” An IOM “SEID” patient group would be much more diverse than either a Canadian “ME/CFS” or even a Fukuda CFS group.

Using a specific version of “ME/CFS” for research and promoting another greatly expanded version of “ME/CFS” for diagnosis makes no sense. If the Nagy-Szakal et al. authors’ claim that “ME/CFS” is diagnosed by the IOM criteria were actually true, absurdly, “ME/CFS” research could not be applied to “ME/CFS” patients. Regarding the IOM report, first, it needs to be always made clear that the fatigue-based condition the IOM criteria diagnose is NOT myalgic encephalomyelitis. From page 11, comments on Recommendation 3, of the IOM “ME/CFS” (“SEID”) report:

“The committee deemed the term “myalgic encephalomyelitis,” although commonly endorsed by patients and advocates, to be inappropriate because of the general lack of evidence of brain inflammation in ME/CFS patients, as well as the less prominent role of myalgia in these patients relative to more core symptoms.”

Clearly, what the IOM report’s US authors are calling “ME/CFS” is not consistent with myalgic encephalomyelitis as extensively described in the medical literature and the 2011 ME-ICC, developed by a far more qualified and experienced, independent international panel.

Also, the IOM criteria are less, not more, specific than even the currently used nonspecific Fukuda-based CFS diagnostic criteria. Case definition expert Dr. Leonard Jason has written about the IOM report:

“The IOM also released a new case definition to replace CFS, and our published work now suggests that these new criteria would almost triple the prior CFS prevalence rate, and this is in part due to the inclusion of individuals who formerly had been excluded. Unwittingly, this inadvertent action accomplished much of what Bill Reeves and the CDC had attempted to do a decade ago when they proposed an ill-fated expansion of the case definition.”

Also, the IOM criteria are inferior to the existing Canadian criteria and would diagnose as “SEID” a significant number, if not a majority, of psychiatric and behavioral disorders, undermining the credibility of any future “SEID” diagnosis. When the unscientific IOM report came out in 2015, ME specialist Dr. Derek Enlander said this:

“At present, the Canadian Consensus Criteria are used by a majority of experts who diagnose and treat this disease; they adhere to the concepts defined by Dr. Melvin Ramsay, who helped pioneer research in this disease, in contemporary clinical settings. Were discussion and debate even necessary, one million dollars could still have been saved – a not insignificant percentage of NIH research funding dollars in this area. Given the paucity of funds allowed for research and study of what we know as Chronic Fatigue Syndrome, it seems, with all due respect, to be a shameful waste of money.”

“The notion to rename the disease Myalgic Encephalomyelitis (which, if we mention, we should also mention ‘Chronic Fatigue Syndrome,’ just to be clear) to “SEID” is highly unnecessary. This will confuse not only patients but physicians who are expert in the disease as well as those who are not familiar with the condition.”

“The criteria that are quoted are a truncated version of the Canadian Consensus Criteria (CCC), truncated in a manner that allows the over-diagnosis of the disease. These criteria would also allow the diagnosis to include psychiatric conditions that are specifically excluded by both the Fukuda and CCC. I am surprised that the experts in the IOM Oversight group has not commented on this.”

Use of the ambiguous term “ME/CFS” allows the IOM report authors to imply whatever it is their criteria diagnose could be ME when, in fact, it is nothing of the sort. However, because the information needed to allow doctors to make the differential diagnosis of ME is suppressed in the IOM report (the critical ME-IC Primer is never mentioned), and because “SEID” has no exclusions whatsoever, there is a major risk of credulous and uninformed doctors misdiagnosing their ME patients with the new “non-existing chimera” fatigue condition “SEID.”

Such a missed ME diagnosis could be tragic because the unscientific IOM criteria, based on cherry-picked “evidence,” require doctors to wait 6 months before giving their patients a nonspecific diagnosis of “SEID.” ME specialists stress the importance of diagnosing ME as soon as possible because, as Dr. Melvin Ramsay has written on many occasions about ME:

“Those patients who are given a period of enforced rest from the onset have the best prognosis.” “Prompt recognition and advice to avoid over-exertion is mandatory.” “Any excessive physical or mental stress is likely to precipitate a relapse.”

Waiting an arbitrary 6 months to diagnose, or misdiagnose, ME, as recommended by the Canadian, Fukuda, and IOM criteria, increases the risk of lifetime disability and premature death for patients with ME. The 2011 ME-ICC do not require a 6-month waiting period for diagnosis:

“No other disease criteria require that diagnoses be withheld until after the patient has suffered with the affliction for 6 months. Notwithstanding periods of clinical investigation will vary and may be prolonged, diagnosis should be made when the clinician is satisfied that the patient has ME rather than having the diagnosis restricted by a specified time factor. Early diagnoses may elicit new insights into the early stages of pathogenesis; prompt treatment may lessen the severity and impact.” http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2796.2011.02428.x/full

Apparently the CFS doctors co-authoring the Nagy-Szakal et al. study do not see a problem with both misrepresenting and effectively endorsing the hopelessly flawed IOM report. By doing so, they ignore the risks that implementation of the IOM report pose for ME patients. It is very concerning that these well-known doctors, in what should be an objective and independent research paper, would place doing public relations work for the US Department of Health and Human Services, which commissioned the IOM report, above good medicine, good science, and the well-being of ME patients.

Conclusion

These are only some of the problems created by the growing use of the ambiguous term “ME/CFS,” instead of keeping the two incompatible diagnoses, ME and CFS, separate. Despite rosy predictions by some commentators that progress, as always, is just around the corner, the failure to use clear terminology and the best research and diagnostic criteria available – such as the ME-ICC, which are both for the clinical diagnosis and research of ME – has created an impasse. It is difficult to understand why there continues to be such great reluctance by professionals in the field of ME and CFS to use clear and consistent terminology.

I believe it is better to face reality than raise false hopes in severely ill and disabled patients. The grim reality is many ME and CFS researchers and doctors continue to show deference to self-serving government agencies by using their unclear terminology and flawed criteria that have been an impediment to progress in research for the last 30 years. This lack of independence and integrity in many ME and CFS professionals has produced only more confusion – ultimately resulting in the continued misrepresentation and neglect of patients. ME and CFS patients deserve better from the professionals in the field.

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