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Can physical assessment techniques aid diagnosis in people with CFS/ME? A diagnostic accuracy study

Discussion in 'BioMedical ME/CFS Research' started by Andy, Oct 27, 2017.

  1. Valentijn

    Valentijn Moderator Staff Member

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    The same Puri who was a lead author from the older paper about just the single Perrin tender spot, and has had his fish oil promoted by Perrin, was Reviewer #1 of this new diagnostic paper :expressionless: It's possible that some of the other reviewers are dodgy too.
     
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  2. Joel

    Joel Senior Member (Voting Rights)

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    Leaving aside the issues around unproven claims being promoted about the treatment, this study created a hamstrung diagnostic method to compare against which had the effect of making the Perrin technique look better than it was.

    If we compare against the actual standard NHS diagnostic practice which was presumably used to diagnose patients taking part in the study in the first place (albeit one performed outside of trial conditions and at an earlier point in time) the Perrin technique fails to achieve the same rate of diagnosis and also produces false positives. Where then is the value from a diagnostic point of view?

    It seems they are highlighting that the examination only takes 20 minutes as a positive (probably about five minutes shorter than the consultation I had when I was diagnosed, not sure what the standard amount of time is for an NHS diagnosis consultation?). Not a huge saving, especially as it would be inappropriate in a clinical setting not to take a history and ask about symptoms anyway. And do we ignore the problem of false positives which the technique introduces? Also we don't know if the technique would perform the same, worse or better at an earlier point in time, at the point where patients receive their standard NHS diagnosis and that may be important.

    And the biggest question of all, as mentioned before: can the Perrin technique tell ME/CFS patients apart from disease and sedentary controls as the current diagnostic method attempts to do. This is a vital test which they've made no attempt to prove yet. Till they do they really should not be claiming success like they are even as a diagnostic method.
     
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  3. Joel

    Joel Senior Member (Voting Rights)

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    Agree that the pathophysiology isn't needed to make something useful either as a diagnostic or a treatment, but the issue here is that Perrin is making claims about pathophysiology without prior proof to back them up while selling the treatment privately. Not sure if anyone is selling Rituximab with such certain claims being made about the pathophysiology and even if they were at least we have two well conducted trials showing the treatment does appear to work in those trials (whatever the reason why).
     
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  4. alex3619

    alex3619 Established Member (Voting Rights)

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    Probably NICE guidelines for patients. If it was Oxford then we can totally discount the study. Does anyone know which diagnostic criteria for sure?

    Current diagnostic techniques are fundamentally flawed, so I agree I cannot have confidence. Where was the validation using CCC or ICC?

    The issue here is we cannot be sure they are wrong. We can, justifiably, have doubts.

    Edit:
    (from the paper)
     
    Last edited: Nov 16, 2017
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  5. alex3619

    alex3619 Established Member (Voting Rights)

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    Big pharma does this frequently using comparison groups, not placebo. Give the wrong drug, in the wrong dose, or with the wrong protocol, and compare it to your drug.
     
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  6. alex3619

    alex3619 Established Member (Voting Rights)

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    Let us suppose this test has a high sensitivity, though current ME testing has sensitivity to 95% which is clearly superior, though more expensive. It still suffers from specificity, which is the bane of a lot of testing. We cannot be sure the findings are not due to other issues.

    Edit: The sensitivity and specificity results given are only as good as the methodological limits. If we did the same thing with other things, like the two day CPET protocol, we could claim 100% specificity, and 95% sensitivity at least. Yet its misleading to do that. We need to cast a wider net, with a large sample size, including many more diseases, to start talking about specificity aside from a technical figure.
     
    Last edited: Nov 16, 2017
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  7. alex3619

    alex3619 Established Member (Voting Rights)

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    For perhaps a decade I did have swollen lymph nodes. Then they went away. Then about a decade ago I came down with a chronic sore throat. I am still waiting for that to go away.
     
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  8. alex3619

    alex3619 Established Member (Voting Rights)

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    Let us be fair though, we should not be requiring this study meet the standards of mature research. Its early days. What we can do is say something like "OK, there is a possibility there is something to this, please do a follow-up study with better methodology. " Most possibilities that are raised in research turn out to fail on follow up.
     
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  9. alex3619

    alex3619 Established Member (Voting Rights)

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    Yes, its the same flaw. However the sentence implies the solution. Do not rely on subjective outcomes, use objective outcomes, then base any claim of success or failure on the objective outcomes. This does not remove the need for sound methodology however.
     
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