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(v. academic) Minimal Important Change (MIC) scores research -international consensus

Discussion in 'Other Health News and Research' started by Dolphin, Jul 2, 2011.

  1. Dolphin

    Dolphin Senior Member

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    I don't claim this is of much general interest but it came up in the PACE Trial where they gave percentages "improved" based on this. I am writing something so decided to research it more.

    I'm writing something at the moment so doing a lot of reading.

    [​IMG]

    Those sorts of scores are quite a bit bigger than the 2 on the Chalder Fatigue Scale (0-33) and 8 on the SF-36 Physical Functioning scale (0-100) used in the PACE Trial.

    For example, if one was to use the 30% of baseline values (mean SF-36 PF: 38.025, mean CFQ: 28.175), the values would have been:

    SF-36 PF: 11.4075 (vs. 8)
    CFQ: 8.4525 (vs. 2)


    Free full text at: http://journals.lww.com/spinejourna...Change_Scores_for_Pain_and_Functional.15.aspx
  2. Esther12

    Esther12 Senior Member

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    Thanks Dolphin.

    With this sort of thing, it seems like the researchers have a lot of leeway to spin their results however they want. It's a bit ridiculous.
  3. oceanblue

    oceanblue Senior Member

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    It's geeky but I like stuff like this...

    I think it's worth noting that there is plenty of genuine debate about how to measure 'meaningful' improvement. Unfortunately this means that any researchers so-minded can exploit the ambiguity to select whichever method best suits their chosen findings.

    However, I think there may be an issue over using percentage of baseline: it seems to matter if 'worse' scores high (eg Chalder) or low (eg SF36).

    Using the PACE examples, 30% of baseline is:
    11.4 for SF36 = 11% of the maximum scale score (0-100)
    8.5 for CFQ = 38% of maximum scale score (efffectively 11-33 ie 22 max, it's 26% of 0-33 scale)

    So - if I've got this right - using percentage of baseline is harder on low-is-better scales like CFQ than high-is-better scales like SF36. Not sure if I've explained this very well - it's something like 30% of a high score will always give a more demanding threshold than 30% of a low score.

    I'm talking principles here, I still feel 2 as the threshold for 'meaningful improvement' is way, way too low on CFQ. I've had a thought on why this might be and will post more if I can knock it into something more coherent.

    Looking at SF36 research on other illnesses I'm pretty sure there was a consensus that a score of 10 counted as clinically significant improvement. that actually tallies quite well with the 30% of baseline rule and also with PACE. A nominal improvement of 8 is actually 10 for any individual since the scale is scored in 5-point increments.

    Finally, I couldn't help noticing that the definition of clinical improvement in this pain study was based on expert opinion. It's a shame they didn't bring patient's view into it too! I think this has been done is some other studies: perhaps the PACE authors might like to try this approach too.
  4. Dolphin

    Dolphin Senior Member

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    As there are at least a couple of people reading this, I thought I'd put a little more time into it.

    Here are a few bits I underlined
    Seems like the language hasn't been standardised:
    I thought the point about time interval might be interesting e.g. one might expect a bigger change over a longer period:
    Lots of debate still:
    and
    Interesting point about different treatments possibly requiring different MICs:
  5. Dolphin

    Dolphin Senior Member

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    I agree.

    However, they did a literature review first and some of the values in some of the studies there could have been from patients' views.
  6. Esther12

    Esther12 Senior Member

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    Thanks for the summary Dolphin.

    From taking the time to close read more papers, I've come to realise how much of what is said in medical papers is so ill defined as to be impossible for front-line staff to really understand it. Very few docotors/CBT therapists/etc will take the time to really understand exactly what the figures/questionnaire scores/etc mean, so they are reduced to relying upon the vague impression created by the write-up's use of language.

    CFS is particularly bad for this sort of thing - but I get the impression it's a fairly widespread problem, affecting lots of medical conditions.
  7. Sean

    Sean Senior Member

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    My impression from reading peer review papers is that there is often a serious problem with disparity between the abstract (which is all most people ever read), and the full content. I have seen others make that comment in other fields of medicine.

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