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Goldsmith et al piece on PACE Trial inc. link to free txt (help sought to explain it)

Discussion in 'Latest ME/CFS Research' started by Dolphin, Dec 27, 2011.

  1. Snow Leopard

    Snow Leopard Senior Member

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    Well her name isn't on the PACE protocol paper, so...
     
  2. oceanblue

    oceanblue Senior Member

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    As the first-named statistician, I assume she did agree to (if not initiate) the changes made, including the post-hoc definition of normal.
     
  3. oceanblue

    oceanblue Senior Member

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    Thanks, Dolphin, you're supreme at retrieving research.

    Thanks to Marco too:
    Interesting point about the problems of measuring the kind of self-report bias that may have taken place in PACE; it seems slightly different from the normal examples of social desirability (eg false answers to Qs like 'do you have a sexually transmitted disease'?).

    There's a problem with fatigue since it's purely a subjective symptom with no objective measure available, so as far as I can tell self-report is the only option. Even if they had therapist rating or therapeutic alliance data for every patient it would be hard to tell if that contributed to self-report bias as there are 2 possibilities:
    1. The therapy works. It works better with a stronger patient/therapist relationship
    2. The Therapy doesn't work, but patients rate themselves better where there is a stronger patient/therapist relationship due to self-report bias.
    I don't know how you distinguish between the two possibilities (it may even be a bit of both).

    I agree there should have been greater use of objective activity measures and it's a real shame they dropped the original plan to use actometers for measuring outcomes. But it's worth remembering the actometers are by no means perfect measures of activity since they measure acceleration, not force (so, for instance, can't tell the difference between climbing a flight of stairs and walking across the living room, while it's a pretty obvious different to a patient). They are very accurate for walking/running on level ground but are much less accurate in 'free-living' humans. Though of course they don't suffer from self-report bias. It may be several measures are needed eg 6MWT, actometers and SF36; ideally someone would do testing first to see which was most accurate at measuring change (AFAIK this has never been done). Maybe such measurements could also establish which would be best as the primary outcome measure.

    Overall, I guess I'm saying it's a complex situation, but PACE didn't really address the complex issues at all.
     
  4. Sean

    Sean Senior Member

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    All these (well known) problems with Social Desirability Bias, etc, just reinforce how critically important it is to use reliable independent objective measures, and use them appropriately (ie also measure for post-exertional features).
     
  5. floydguy

    floydguy Senior Member

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    What reliable objective measures do you suggest for post exertional features?
     
  6. Dolphin

    Dolphin Senior Member

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    (Repeating points I've said before, but it is another thread) There are different sorts of motion sensing devices. Some work in three-dimensions which might get around the problem you mention.

    Also, while on an individual level it might not be as good as double-labelled water (say), I would think in aggregate form (and (arithmetic) means are aggregates) actometers would still be preferable to SF-36 PF (say).
     
  7. Sean

    Sean Senior Member

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    Repeating an objective or relatively objective test (actometer, 6 minute-walk-test, oxygen uptake, gene expression, neuro-cognitive capacity, etc) 24 hours or so later, and then maybe again 3-4 days after that. Not perfect, but a major methodological improvement on just using non-repeated, subjective self-report for post-exertional features, which is what PACE did.

    And yes, oceanblue, actometers are not perfect. Nobody is arguing that they are the final word, just that they are substantially more objective than self-report based measures, and should be routinely used, especially when baseline data already exists. They bring a little more honesty about results to the table. Besides, controlling for the significant use of stairs in a patient's daily life shouldn't be that hard, and could provide some useful info.

    I agree there needs to be a constellation of measures, including employment levels, and various subjective measures. But ultimately if the more objective measures don't show a good result, then all the glowing subjective self-reporting adds up to diddly squat. Which is really the main problem with results from the psych based studies minimal correlation between subjective and objective outcomes, specifically, unduly favourable subjective reports with no objective support.
     
  8. oceanblue

    oceanblue Senior Member

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    My point is that there isn't any good data to show which is best*, particularly for measuring change after therapy, and I suspect a composite measure may be required. Adding 3D over 2D wouldn't necessarily help, unfortunately, if it still measures acceleration rather than load. Aggregate form should help, but not if actometers have systematic errors and again there is no data. The manufacturers of these devices seem to content themselves with tests in unrealistic lab-based scenarios, where they are indeed highly accurate.

    And we still have the problem of fatigue, where there are no objective measures available.

    * what would be good - and PACE would have been an ideal opportunity to do this given their budget - would be to use double labelled water vs SF36, actometers, and any other plausible measures both before and after therapy in a sub-sample of patients. Then see which most accurately reflects the double labelled water figures. Without data we remain in the dark as to the most reliable measures of activity. However, the discrepancy between PACE self-rated items and the 6MWT - and the low 6MWT distances compared to data on healthy subjects - do show that SF36 are highly suspect as the sole primary outcome measure..
     
  9. Dolphin

    Dolphin Senior Member

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    Perhaps this should get its own thread?

    From:

     
  10. Dolphin

    Dolphin Senior Member

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    Another abstract:
     
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  11. Dolphin

    Dolphin Senior Member

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    Another abstract - looks similar to last one


     
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  12. Esther12

    Esther12 Senior Member

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    Looks like they're doing more digging in to the data to try to find 'positive' results to publish. If the evidence really supported their views, they could just release the data as it was laid out in the protocol, and let the evidence speak for itself.

    It would be funny if the Goldsmith data transformed into the papers above:

     
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  13. Dolphin

    Dolphin Senior Member

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  14. Dolphin

    Dolphin Senior Member

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    K Goldsmith did her PhD on the PACE Trial data.

    https://kclpure.kcl.ac.uk/portal/en...me(413e5fb0-03b9-40bc-b993-0465b1bcbdee).html

    FWIW:

     
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