To PENE or not to PENE
The criteria I guess may be much like the canadian consensus one. There is many patients who have CFS who dont fit that criteria hence there will still be division. What happens to those patients? There needs to be division as not everyone has got the same or even similar things going on.
Good question. The full criteria in this new international ME definition seems stricter than the older Canadian criteria, both the original and revised versions:
"A patient will meet the criteria for post-exertional neuroimmune exhaustion (A), at least one symptom from three neurological impairment categories (B), at least one symptom from three immune/gastro-intestinal/genitourinary impairment categories (C), and at least one symptom from energy metabolism/transport impairments (D)."
However, there is still looser criteria for Atypical ME:
"meets criteria for post-exertional neuroimmune exhaustion but has two or less than required of the remaining criterial symptoms. Pain or sleep disturbance may be absent in rare cases."
ME focuses on impairments in function due to multisystem "post-exertional neuroimmune exhaustion" (PENE) rather than the chronic central fatigue of CFS. So the main division here seems to be whether patients experience PENE. I haven't cross examined in detail yet but I have a hunch that Canadian criteria for post-exertional symptoms may be slightly less strict than PENE.
According to a study (
http://www.biomedcentral.com/content/pdf/1756-0500-4-139.pdf) about half of those who meet Fukuda CDC criteria will meet Canadian criteria, at least those who where "identified in GP databases using a READ-code based algorithm", something which I have doubts about since there is no guarantee the patient volunteered all their symptoms or that the GP's wrote down all the patient's symptoms (especially if skeptical or even dismissive about them). But this gives us a roughly idea that the "wider CFS community" could be split in half over this issue.
According to the revised Canadian definition, "
Within a group of individuals diagnosed with CFS, Jason et al. (1999a) found that post-exertional fatigue or malaise for individuals with CFS ranged from 93.8-40.6% depending on how the question was asked." The Canadian definitions of post-exertional symptoms were always more descriptive than CDC/Oxford, and the new ME criteria carries on this fine tradition. Obviously there is some ambiguity in the term "post-exertional fatigue/malaise" (which biopsychosocialists try to portray as the effects of deconditioning and/or psych-behavioural disturbed homeostasis), and those that experience PEM do not necessarily meet criteria for PENE and those that do not meet PENE criteria cannot be diagnosed with ME.
So what happens to those people who don't meet either ME or Canadian criteria? Unless there are major changes in the CFS labyrinth they may remain stuck there, and so will everyone else as well if the international ME definition doesn't facilitate change for ME patients. I don't think anyone who doesn't meet ME criteria should be abandoned for having an alleged biopsychosocial illness. The problem with CFS criteria is that it has always been relatively non-specific, a wastebasket diagnosis with potentially multiple types of medical conditions and lumped in with overlapping psychiatric diagnoses. Canadian and now international ME criteria has been a step in the right direction for carving off a large slice of this heterogeneous pie and loosening the stranglehold of a broad approach.
If there really is a general fatiguing biopsychosocial illness as conceptualized by Oxford criteria and Reeves' CFS, the split will be helpful for them too. However, much of the cited research in this new international ME definition used Fukuda criteria for CFS. Those that don't meet ME criteria may still have similar pathology and/or have a condition that isn't helped by the biopsychosocial approach. Having seen how "psychogenic/somatization/functional dismissal by default" has plagued the ME/CFS community for decades, I am cautious about leaving the non international ME and non Canadian ME/CFS patients out in the cold, but I meet both so naturally I'm going to be more concerned about patients and research that better reflect me.