Thanks to Bob and Mark for those extensive posts, which really got me thinking.
I think that, right now, the most important thing our entire community needs to be pushing for is for a separation of ME from other fatiguing illnesses.
I think that all of our patient organisations need to come together to organise a big, single, concerted campaign to fight for the Canadian definitions, or better, to be used, so that ME can be treated as a single, distinct, disease in its own right.
I fully agree with the first point as I think it's key both to effective research and to how patients are diagnosed and treated. As for the definition we push for, it might be the 'or better' option, I think, for many reasons, including those made by Mark, Bob and WillowJ - though I agree that the CCC are the right place to start that discussion.
As Mark says, patients who don't quite meet the CCC are likely to feel cast out from the ME tribe yet certainly don't feel they they have some general chronic fatigue that the biopsychosocialists love to prey upon
Mark: Talk about being caught between the devil and the deep blue sea!
I completely agree that if we can all unite around a common view of the illness we are far more likely to make a difference.
Bob's point that people like Nancy Klimas, Judy Mikovits and Lenny Jason recognise that some of their patients would no longer fit the CCC, to me highlight one of the weaknesses of the criteria as they currently stand.
at the 2010 Invest in ME conference, Mikovits, Whittemore, Klimas and Jason confirmed that the experience they have with many of their patients was that their symptoms had changed over time, esp after employing symptom management techniques (such as pacing, and whatever other medical tools they used to get better). The four speakers at the round table discussion seemed to be under agreement that their patients' symptoms changed over time, and that they expressed quite different symptoms, and levels of symptoms over the course of their illness. They said that some of their patients would not necessarity fit the Canadian consensus criteria (CCC) now, whereas they would have done when they were first ill.
As these participants and Bob suggest, we could broaden the definition of CCC to evaluate patients over the course of the illness. Or do as Lenny Jason does (pointed out by Dolphin) by having several levels of CCC criteria. It's certainly possible, but my concern about this approach is that it takes a complex definition, and when it doesn't quite give the right answers, adds yet more complexity until it does.
There's an Albert Einstein quote that I think very relevant:
Everything should be made as simple as possible, but not one bit simpler
The Oxford Criteria to me fail the second part of this test: by focusing just on mental and physical fatigue they too broad to be useful, sweeping up a whole mish-mash of patients many of whom have primarily psychological problems with fatigue as a secondary factor.
On the other hand, I seriously wonder if the enormously complex Canadian Criteria meet the 'as simple as possible' test (which is much the same as
Occam's Razor). Have you read the CCC document? It lists so many requirements that in lots of different places I couldn't help wondering - are we sure this is the
exact place to draw the line between ME and not-ME?
As Mark put it:
if the line is going to be drawn at the CCC, if you want to achieve that separation, then firstly you need some damn good evidence that sharply distinguishes that condition from anything that falls just short of it
It turns out that is a key principle in defining diseases in general (bonus points to Mark
) - if the people who meet the cirteria look very much like those that just fail to meet them, then you probably haven't defined a discrete illness.
Digression to main thread topic There's a really interesting paper about the
validity of psychological diagnoses which concludes that most psychological illnesses are not valid disease entities ie that the current DSM-IV is full of diseases that aren't really valid specific diseases at all! Never mind DSM-V proposals... Maybe that's why psychologists are so comfortable with definitions of CFS that don't tie down a discrete illness?
The key point that the paper makes (it's not just talking about psychological disease) that I think is relevant to ME is:
Diagnostic categories defined by their syndromes should be regarded as valid only if they have been shown to be discrete entities with natural boundaries that separate them from other disorders.
My concern is that there might not be a natural boundary between those that meet the CCC and those that just miss out.
What would help here is
empirical evidence (no relation to the dodgy CDC 'empirical criteria') to find where, if anywhere, the natural boundaries exist ie the point Mark made above. My guess would be that there are natural boundaries with CCC inside the boundaries but with them quite a lot of patients who have things like PEM but don't currently meet every last CCC criteria.
But I have no evidence for that hunch and I think evidence is what's really needed to move this forward. Evidence would have the huge advantage of moving the debate from 'this is what physicians and patients recognise and believe describes the illness' to 'here's the evidence that this definition describes a unique group of people with a common illness, clearly distinguishable from other forms of chronic fatigue'. It might turn out to be the CCC exactly as they are described now, it might be something a little broader - but at least any refined defintion would be based on how well it identifies unique patients in the real world. The experiment would be something like take a big bunch of chronically fatigued patients, collect a mass of data on them including lab test, demographics and everything required for the CCC, then use data analytical techniques such as Factor Analysis to see if groups of patients cluster together.
It may be that if you specify just a few symptoms e.g. PEM, Post-exertional Fatigue and mental concentration/memory problems a discrete cluster will emerge that will include all the CCC patients as well as others who don't quite meet CCC. We won't know unless someone does the experiment.
Bob's proposal's
1. The first is to evaluate the patient's symptoms over the entire course of the illness, from the very beginning to the present time
That would certainly be one way to do it, though I'm sure there would be objections from some to a diagnosis based on symptoms that may not have been present for 15 years
2. The second solution would be to use the CCC only for research purposes, and not in a clinical setting.
Again, I think this is one way forward, but I have 2 concerns. The first is practical: because of the need for a full medical evaluation it's expensive/time consuming to screen patients, which is presumably why so many studies are so thin on patients. Using highly restrictive criteria will make recruitment even harder but not necessarily better. The second isn't an objection as such, but if there were
empirical evidence for the criteria it would be a whole lot easier to persuade researchers that these criteria are the way to go.
3. The third solution would be to have different levels/grades of ME,
Unreservedly agree that sub-grouping would be useful! Though as bob notes, the more you sub-group, the less generally applicable the findings.
4. The fourth, is that if we all agree that ME has to have post exertional malaise (PEM) as a symptom
Agree with this one too, as does WillowJ, it seems. But it isn't currently mandatory in CCC, which only require PEM
OR post-exertional
fatigue.
Summary
Phew, this has gone on a bit! Here's what I've been trying to say:
1. I agree that getting everyone behind a case definition that separates ME from general chronic fatigue is incredibly important. I also agree that the CCC are a good place to start but as they are currently defined they do seem to exclude a lot of people, potentially alientating many patients and the exclusions may not work as intended all of the time (as observed by Klimas, Jason, Mikovits).
2. I think some empirical research might resolve these problems. We could see if the CCC defines an discrete illness with natural boundaries or if some of the CCC boundaries are artificial and need tweaking. It's just possible that the CCC could be made even better.