Dr David Tuller: A Q-and-A with Leonard Jason on Case Definition

[Countrygirl]

http://www.virology.ws/2018/05/02/trial-by-error-a-q-and-a-with-leonard-jason-on-case-definition/

Trial By Error: A Q-and-A with Leonard Jason on Case Definition
2 MAY 2018
By David Tuller, DrPH

A Brief Update: Berkeley’s crowdfunding period closed on April 30th–Monday night. I ended the campaign with $87,580. After Berkeley’s 7.5% in fees, the funds will cover my salary/benefit from July 1, 2018 to June 30, 2019, and some travel costs. I really, really appreciate the fantastic support. Thanks to everyone! I’ve taken a few days to regroup from my Australia trip and catch up on my time zones.

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Leonard Jason is a professor of psychology at DePaul University in Chicago. He has served as vice president of the International American Association of CFS/ME and as chairperson of the Research Subcommittee of the U.S. Chronic Fatigue Syndrome Advisory Committee. Professor Jason began investigating chronic fatigue syndrome almost 30 years ago. Much of his work has focused on the epidemiology and prevalence of the illness and on the impact of using various case definitions. He has long been concerned that the lack of a uniform set of criteria for identifying study participants has hindered progress in the science.

Dr. Jason recently shared his thoughts about these issues. (This Q-and-A has been edited for clarity and length.)

 

[Ravn]

Totally agree with the gist of the interview: we need good case definitions to get good research results. No argument.

But there's a very strange statement in this paragraph (bolding mine):

the IOM report was correct in requiring several core symptoms, such as PEM. But I believe these authors made a mistake in indicating that a patient could have either cognitive impairment or orthostatic intolerance—one or the other. Cognitive impairment should have been required for all patients to have. But a more serious problem is that they inadvertently expanded the case definition by having just about no exclusionary illnesses, such as primary psychiatric disorders. My team recently conducted a study where about half the people with a variety of medical and psychiatric illnesses met the IOM criteria.

This is effectively saying that “ about half the people with a variety of medical and psychiatric illnesses” actually have PEM. How can this be? Some serious issue with defining PEM here, surely!

 

[nanonug]

This is effectively saying that “ about half the people with a variety of medical and psychiatric illnesses” actually have PEM. How can this be? Some serious issue with defining PEM here, surely!

This is a good point. There are (at least) two possibilities:

1. The definition of PEM, whatever it is, is fuzzy enough that conditions other than SEID have it as a symptom; or,
2. PEM, even if properly defined, is not the great differentiator we thought it was

Personal, I'm not a fan of "mental PEM". I'd like to see PEM objectively defined by making use of the 2-day CPET and making it therefore unequivocally "physical."

 

[alex3619]

I wrote a long detailed reply to this on the blog. It seems to have vanished. I am hoping its just in moderation.

Basically it was 1. we need validated PEM biomarkers, and 2. somatoform disorder is an hypothetical disorder with no test and no scientific evidence, its imputed based on scientifically unvalidated definitions.

 

[alex3619]

Totally agree with the gist of the interview: we need good case definitions to get good research results. No argument.

But there's a very strange statement in this paragraph (bolding mine):



This is effectively saying that “ about half the people with a variety of medical and psychiatric illnesses” actually have PEM. How can this be? Some serious issue with defining PEM here, surely!

If comment on the blog ever appears it addresses this. There is NO quality scientific evidence that the biochemistry of PEM found in ME patients matches that of other disorders. Its not enough to infer PEM, we need valid biochemical or other biomedical measurements.

 

[alex3619]

This is a good point. There are (at least) two possibilities:

1. The definition of PEM, whatever it is, is fuzzy enough that conditions other than SEID have it as a symptom; or,

I have said before that most doctors will probably misdiagnose PEM. There are no substitutes for objective markers. How PEM is operationalised can invalidate a study. If Jason is saying that I would agree. However if he is saying that PEM is found in other disorders I want to see the objective evidence. While diagnosis based on symptom checklists might be OK clinically, its not OK in clinical trials.

 

[Ravn]

If comment on the blog ever appears it addresses this. There is NO quality scientific evidence that the biochemistry of PEM found in ME patients matches that of other disorders. Its not enough to infer PEM, we need valid biochemical or other biomedical measurements.

Excellent. I do hope your comment will eventually appear.
I see @Valentijn made a similar and very good comment:

I also have trouble believing that a study would find a high prevalence of ME using the IOM criteria, if PEM were appropriately defined. It's an area where Jason has struggled in the past (perhaps resenting criteria he did not develop), and I don't have a lot of faith in his research involving criteria. He also seems to conflate PEM with a more common form of exercise intolerance (which ME patients may have in addition to PEM), potentially beginning immediately after or even during exertion, rather than being substantially delayed.