What Does a True ME Definition Look Like?

 CFS vs ME: A broad definition causes you to study several diseases as if it were one - a disaster for research.


This is the second in a series of articles explaining our goals. The second goal is get a true myalgic encephalomyelitis (ME) definition established. 

A great metaphor for chronic fatigue syndrome (CFS) is the chimera – a ferocious creature from Greek mythology. The chimera is made up of several creatures, the head of a lion, the body of a goat, and a snake for a tail. The Miriam-Webster dictionary puts it like this - “an imaginary monster compounded of incongruous parts.”

What does this have to do with CFS? The 1994 Fukuda case definition for CFS is very loosely defined with an overly broad reach. Like the chimera, it describes many different and unrelated “animals” all mashed into one – not only myalgic encephalomyelitis (ME), but also major depression, iodiopathic chronic fatigue, and undiagnosed major illnesses, such as multiple sclerosis*. This is called a low specificity definition, i.e., attempting to define ME, but hitting far from the mark.

This is one reason why researchers have a tough time coming to any conclusions regarding CFS, and why the patient population is often described as heterogenous (not all the same) – because they aren’t!

As you can see from the infographic above, based on average of six studies comparing the Fukuda Criteria (the current CFS definition), to the Canadian Consensus Criteria (the most widely used ME definition), 65% of people diagnosed with CFS have ME, while 35% do not. That means all the studies to date using the Fukuda Criteria include a large percentage of people who do not have ME. This has been going on since 1994.

In contrast, our proposed true ME definition (the Canadian Consensus Criteria, International Consensus Criteria, or better) is a tightly defined, or high specificity definition. It defines ME and nothing else. Referring back to the chimera metaphor, this would be like describing only one animal, such as a lion. Imagine how much improved and relevant research would be if you were only studying one disease. Makes sense, doesn’t it?

ME patients deserve to have a high specificity definition, just like other diseases. That’s why our goal is to get ME officially recognized as its own distinct disease along with a true ME definition (the Canadian Consensus Criteria, the International Consensus Criteria, or better).

*List of diseases that can be misdiagnosed as CFS (other than M.E.) - mind blowing! http://www.hfme.org/meandmisdiagnosis.htm

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Click here to for more info and to donate: https://meadvocacy.nationbuilder.com/donatepr


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Leonard Jason presentation, Dec. 9 2014 – starting at 1 hour 1 minute
Luis Nacul presentation, Dec. 9, 2014 – starting at 2 hours 22 minutes

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Jason LA, Torres-Harding SR, Jurgens A, Helgerson J. Comparing the Fukuda et al. criteria and the Canadian case definition for chronic fatigue syndrome. J Chronic Fatigue Syndr. 2004;12(1):37–52.
20 CCC / 32 Fukuda = 62%
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Contrasting case definitions for chronic fatigue syndrome, Myalgic Encephalomyelitis/chronic fatigue syndrome and myalgic encephalomyelitis.
Jason LA, Brown A, Clyne E, Bartgis L, Evans M, Brown M
Eval Health Prof. 2012 Sep; 35(3):280-304.

“…using the symptom frequency and severity cutoff points as specified by Jason et al. (2010), only 50% met the ME/CFS criteria.”

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Contrasting Chronic Fatigue Syndrome versus Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.
Jason LA, Brown A, Evans M, Sunnquist M, Newton JL
Fatigue. 2013 Jun 1; 1(3):168-183.

“However, the current study suggests that about 75% of patients meet the ME/CFS criteria, as this percentage was replicated across three samples when the DSQ was used as the assessment instrument.”

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Prevalence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in three regions of England: a repeated cross-sectional study in primary care

Luis C Nacul, Eliana M Lacerda, Derek Pheby, Peter Campion, Mariam Molokhia, Shagufta Fayyaz, Jose CDC Leite, Fiona Poland, Amanda Howe, Maria L Drachler
BMC Med. 2011; 9: 91. Published online 2011 July 28. doi: 10.1186/1741-7015-9-91
127 CCC / 270 Fukuda = 47%

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Benefit from B-Lymphocyte Depletion Using the Anti-CD20 Antibody Rituximab in Chronic Fatigue Syndrome. A Double-Blind and Placebo-Controlled Study

Øystein Fluge, Ove Bruland, Kristin Risa, Anette Storstein, Einar K. Kristoffersen, Dipak Sapkota, Halvor Næss, Olav Dahl, Harald Nyland, Olav Mella
PLoS One. 2011; 6(10): e26358. Published online 2011 October 19. doi: 10.1371/journal.pone.0026358
28 CCC / 30 Fukuda = 94%

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A Disease Register for ME/CFS: Report of a Pilot Study

Derek Pheby, Eliana Lacerda, Luis Nacul, Maria de Lourdes Drachler, Peter Campion, Amanda Howe, Fiona Poland, Monica Curran, Valerie Featherstone, Shagufta Fayyaz, Dikaios Sakellariou, José Carlos de Carvalho Leite
BMC Res Notes. 2011; 4: 139. Published online 2011 May 9. doi: 10.1186/1756-0500-4-139

97 CCC / 155 Fukuda  = 62%

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Fatigue. 2013 Jun 1;1(3):168-183.
Contrasting Chronic Fatigue Syndrome versus Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.
Jason LA1, Brown A, Evans M, Sunnquist M, Newton JL.
“These consistent findings across the three data sets suggest that about three fourths of those within disparate samples meet the case definition for ME/CFS, whereas the Fukuda et al. criteria identify a larger group of patients.”
In a different sample in the Jason et al. [4]  study (the 2004 one), only 50% met the ME/CFS criteria when the symptom frequency and severity cutoffs specified by Jason et al. [13] were employed. However, the current study suggests that about 75% of patients meet the ME/CFS criteria, as this percentage was replicated across three samples when the DSQ was used as the assessment instrument.

Showing 6 reactions

  • Kit
    commented 2015-02-24 20:50:23 -0500
    Of particular importance to this page is Jason et al. report of the Reeves empirical criteria, which deduced that "38% of patients diagnosed with major depressive disorder were misclassified as having CFS

    and only 10% of patients identified as having CFS actually had ME."

    Jason LA, Najar N, Porter N, Reh C. Evaluating the Centers for Disease Control’s empirical chronic fatigue syndrome case definition. J Disabil Pol Studies 2009; 20: 91–100. doi:10.1177/1044207308325995. Accessed on 10February 2011 at http://dps.sagepub.com/content/20/2.toc.
  • Kit
    followed this page 2015-02-18 18:01:53 -0500
  • Kit
    commented 2015-02-18 18:00:46 -0500
    This chart is missing the Ramsay definition for M.E.; no other definition focused on the characteristic muscle weakness of M.E., which no other disease demonstrates. It used to be considered the anchor of the diagnosis, but has been replaced with generalized weakness instead of muscle weakness in the CCC and ICC. I’ve been reading the Doctor’s book today, detailing all of the outbreaks, and it was the only thing that separated M.E. from the other postviral fatigue states. Something so CRITICAL cannot be left out of our message and deserves more prominence than the ones exclusively listed under “proposed”—because in them, that muscle phenomenon is not even crucial to our diagnosis. Yet it is the reason I’m having to type these messages with my voice instead of being able to type today.
  • Guido Den Broeder
    commented 2015-02-02 20:20:07 -0500
    Actually, the Fukuda criteria (as all CFS criteria) exclude ME entirely, since ME is a known disease that explains the medical complaints. ME patient only happen to get included in Fukuda studies because researchers are oblivious to this.
  • Humwit Bone
    commented 2015-02-02 16:20:43 -0500
    There is no doubt that the situation as you describe Must Be Changed. ME needs to be deciphered as the horrid disease it is, and CFS worked on according to its’ symptoms. Definitely this separation must take place or research isn’t reliable.
  • Geoff Langhorne
    commented 2015-02-02 14:16:36 -0500
    A rigorously accurate definition can only aid researchers and patients. This questioning the Fukuda definition is productive.