I can't help but wonder if this will be a repeat of the past.
So far Dr. Unger stands by the Reeves
et al. (2005) definition and “the estimate, based on the empiric criteria, that 4 million people in the U.S. have CFS.” David Tuller
writes that “others outside the CDC dismissed the new numbers as absurdly inflated and argued that the empiric criteria, like the Oxford criteria but unlike the 2003 Canadian case definition, blurred and expanded rather than clarified the disease boundaries.”
Blurring and expanding rather than clarifying disease boundaries seems to be something that Dr. Unger learned from Dr. Reeves. The ICC recommends that ME patients “should be removed from the Reeves empirical criteria and the National Institute for Clinical Excellence (NICE) criteria for chronic fatigue syndrome.” But rather than separating ME from CFS as recommended by the ICC, the CDC now subsumes ME (ICC) under CFS and seems to be engineering its expansion as well with the statement, "This ME case definition extends the criieria to an extended number of subgroups...."
In a nod to the NICE Guidelines perhaps, Dr. Unger writes of the “Canadian Consensus Criteria of CFS/ME (
sic).” Her methodology for reviewing CFS (Fukua) presupposes that there is one disease, with differences being matters only of degree. Like Reeves
et al. (2005), she relies on “introducing standardized questionnaires and measurement scales to assess levels of fatigue and functional impairment” in the context of already existing domains: “We are planning to collect standardized data on all the domains of illness included in the Canadian Consensus Criteria of CFS/ME (
sic), the 1994 CFS definition and the newly proposed International ME definition.”
Cort
writes of Dr. Unger that:
She believes in the big box approach and a definition (Empirical Definition) that gathers together many different types of “CFS’ rather than a narrower definition which might produce a ‘clean’ group of patients. She acknowledges the need to find subsets – yet doesn’t appear to be committed to producing large enough studies to ferret them out.
In resisting a narrower definition, Dr. Unger resists too the exercise challenge:
Dr. Unger said that her group is looking at all of the instruments and cutoffs used and how they affect who does and does not meet the definition of CFS. She added that the CDC gleaned some interesting information from the exercise challenge; then the decision was made to try a different kind of challenge. This is not to say that exercise is not a good challenge, she said. Researchers want to see CFS in motion; a static picture is harder to understand than observing responses.
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Here's Dr. Unger's more recent position on the best instruments to use:
Dr. Unger: We did not try to reach consensus or recommendations on instruments. We are saying that you have to measure function in some way, and these are some current options. We did not think we could reach consensus on what the best instruments are at this point. There is a separate group that is trying to come to consensus about what best instruments are. Even then, it will not be absolute. There will be criteria that are used to evaluate instruments.
Tellingly, Dr. Unger describes the CDC's current case-definition process this way:
We are going to start with data collection. The question being asked over and over is, how do the patients differ in people’s practices and is this really why we have some problems even though everybody calls it CFS and they are using a case definition? Is that why the findings in the laboratory are not always translatable? That is step number one.
Step number two is, if we have good measures of the domains (and as you know, the field is ongoing as to what are the best measures of the domains), then we try to say how can we capture this the best way. We as a field need to be a little schizophrenic and say yes, we can bring people in under a broader umbrella diagnosis, but then we cannot just group cases and controls. We have to be doing some stratification. We have to use a dynamic range in all of those measures. It is not enough to have just fatigue, but how much fatigue? It is not enough to have any one measure.
I read here Dr. Unger's continued rejection of a test-retest protocol. I expect her new CDC definition to again blur and expand rather than clarify disease boundaries.