Invest in ME Conference 12: First Class in Every Way
OverTheHills wraps up our series of articles on this year's 12th Invest in ME International Conference (IIMEC12) in London with some reflections on her experience as a patient attending the conference for the first time.
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GETSET (white) in Lancet 22/06/17

Discussion in 'Latest ME/CFS Research' started by Esther12, Jun 22, 2017.

  1. Barry53

    Barry53 Senior Member

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    I've been doing some homework on the PACE FOI-released data, regarding perceived Vs actual physical function, and being as GETSET shares the same issues, I'll post some charts here, four of them in all. Click on a chart to magnify it.

    upload_2017-7-7_10-51-7.png

    upload_2017-7-7_11-8-14.png

    upload_2017-7-7_11-10-34.png

    upload_2017-7-7_11-11-9.png

    Notes:-
    1. The charts show % improvement, not absolute improvement. So someone who did 10m at baseline and 15 at 52 weeks shows 50% improvement, same as someone who did 100m at baseline and 150 at 52 weeks.
    2. The charts are all about comparing a person's perceived percentage physical function improvement Vs actual % physical function improvement.
    3. Remember PACE interprets a "50% increase from baseline in SF-36 sub-scale score as a positive outcome".
    4. Each table, within each trial arm, show participants (X axis) from the lowest % increase in actual physical function, through to the highest % increase in actual physical function.
    5. For each participant, their perceived physical function % improvement is shown, as well as their actual % physical function improvement.
    6. The Y axis is % improvement. Negative values mean % PF decreased at 52 weeks compared to baseline. 0% means no change between baseline and 52 weeks.
    7. Perceived PF is as per the SF-36 PF sub-scale, and actual PF as per the 6 min walk test.
    8. In the data there are some participants who rated their PF at 0% at baseline, which gives divide-by-zero if trying to gauge % increase. I have got around this by treating their baseline as 1%, which still shows the expected sharp spike in % change, but keeps the values finite. I didn't want to exclude these participants, because they are a good indication of the disconnect between perceived and actual % PF improvement.
    9. There were quite a lot of drop-outs in the PACE data, with NULL results. These are excluded from the charts.
    Edit: Having read @Snow Leopard 's posts and thought about them a little, I agree that the 6mwt itself is likely not wholly objective. But I think that just means if there were results for a wholly objective measure, it would just show an even bigger disconnect between the subjective (SF-36 PF) versus the objective.
     
    Last edited: Jul 7, 2017
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  2. Snow Leopard

    Snow Leopard Hibernating

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    The 6mwd is not really an objective measure of improvement either, as it reflects motivation and experience with walking, rather than underlying fitness and fatigue.

    Also, as I previously mentioned, GET is a CBT type therapy, as explained by Peter White:
    The lack of exercise and avoidance of activity are (hypothesised) as being key perpetuating factors by Peter White.
    http://www.meactionuk.org.uk/PROOF_POSITIVE.htm
     
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  3. Barry53

    Barry53 Senior Member

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    I'm sure you are right, though I think it will be considerably less subjective than answering obtuse questions about how you think your physical function is.
     
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  4. Snow Leopard

    Snow Leopard Hibernating

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    Well I literally just went out for a walk. Walking as fast as I can, I walked a bit over 800m in 6 minutes (Google maps & Street directory). I really went all out, it hurt like hell. (By the way, one of my family members is a multi-day endurance athlete and I've always had high mental endurance). I can barely walk now.

    Cue the "you don't really have ME" comments, but really, I think the 6MWD cannot be considered an unbiased measure of impairment due to this disease.

    Additional edit - for anyone who doesn't know where 800m fits in the grand scheme of things, well, 800m is not exactly athletic, but it is higher than any participant in the PACE trial (641 enrolled patients).
     
    Last edited: Jul 7, 2017
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  5. Barry53

    Barry53 Senior Member

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    I notice the test actually involves repeatedly walking up and down a 10m stretch, which I imagine is somewhat different to a straight linear walk. The constant stopping and turning must add additional energy consumption (stopping and starting always does ), as well as balance implications. And as you suggest, it must also be a bit soul destroying.
     
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  6. Snow Leopard

    Snow Leopard Hibernating

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    This is true. But the key is that there is huge possible variance in individuals for the 6MWD. The mean walking distances in the PACE trial were in the 300-350m range - very low scores! Some people in the PACE trial had extremely low distances <200m, which suggests they are either very ill, or simply didn't bother to try at all. If you believe the 6MWD are valid, then you could also argue that this shows that despite fairly nonspecific diagnostic criteria (Oxford), they still managed to recruit a very ill group of patients - who remained very ill after the treatment concluded!
     
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  7. trishrhymes

    trishrhymes Senior Member

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    I'm not going to try it because I don't want to set off a relapse. My estimate is that if I did this at home, I would walk the first 10m, sit and rest for 1 minute, walk the next 10m, sit and rest for 3 min. Stagger the last 10m. Total 6min walk test 30 metres. On the other hand if I had to travel to the clinic first I would arrive in a wheelchair pushed by someone else, and feel too ill to walk at all. On that basis I'm either very ill or not trying hard enough, take your pick!
     
  8. A.B.

    A.B. Senior Member

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    I'm sorry to hear you're so ill.

    Agreed. We don't know for sure what the best way to objectively measure impairment is. It's probably CPET because there are standardized protocols, but that's also hard on the patient.

    The walking test almost certainly is more objective than fatigue questionnaires. I have seen many times how other patients say they're feeling good but soon afterwards crash. Difficulty in predicting how much the patient can do seems to be a characteristic of the illness.
     
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  9. trishrhymes

    trishrhymes Senior Member

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    Probably, and the fact that none in PACE could walk far at the end is a signal that the treatment doesn't work. But I agree the 2 day CPET would be a much better measure, but only with patients well enough to cope with the PEM it sets off, so again, only on mildly affected patients.

    When I was mildly affected, ie for the first 12 years when I still (just) managed to hold down a job as a part time teacher while raising a family, I probably could have managed (I'm guessing here) 300m in 6 mins, but I would have crashed the next day or days.

    Sorry, I can't remember the title of this thread. I'm probably straying way off topic. Having a bad day!
     
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  10. Artstu

    Artstu Senior Member

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    I can match that, that's just shy of 5 mph. Given we're both ill it certainly isn't a good indicator of just how ill we really are.
     
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  11. Barry53

    Barry53 Senior Member

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    I wouldn't mind betting the 6mwt might show a reduction of as much as 50% compared to the same linear distance walked. When a person "brakes" they not only lose the momentum gained, but have to expend more energy to slow down, a bit like reverse thrust when an aircraft lands - it is consuming additional fuel to slow down. (Yes I know we are talking somewhat different velocities here, but the principle still applies :)). Then the person has to expend more energy to get to their walking speed again, to recover the momentum lost. In addition there is energy, both physical and cognitive, to process just turning in 180° opposite direction, which for a lot of people with ME is going to be significant. Then there is the subjective bit that @Snow Leopard noted - trudging up and down a corridor over and over and over again is going to make many people lose the will to live anyway, let alone the will to keep on walking.
     
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  12. A.B.

    A.B. Senior Member

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    The 6 minute walking test was also performed by patients who had to travel there first.
     
  13. Barry53

    Barry53 Senior Member

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    Being the pedant I am, a minor correction. Despite what many people say, there were actually 640 participants. The first participant is on row 2 of the spreadsheet, and the last on row 641. Row 1 has the column headings.
     
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  14. Barry53

    Barry53 Senior Member

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    A very valid point. Apart from anything else they had probably already trudged plenty of corridors before it started.
     
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  15. Barry53

    Barry53 Senior Member

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    Actually that is a hell of a walking rate. But ME being what it is, the effects will vary hugely, let alone the PEM that sets in after. I've been looking at a walk my wife and I do with frequent stops (else she couldn't do it), and it comes out at around 1 to 1.5 mph.
     
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  16. Barry53

    Barry53 Senior Member

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    The odds are I suspect Trish that you would have been excluded from the start as someone they might have considered unlikely to be able to reliably/regularly attend and do all the sessions. So a prime candidate for investigation would never have featured in the trial outcomes anyway.
     
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  17. dangermouse

    dangermouse Senior Member

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    Exactly, that'd apply to me too. At this time it's doubtful I'd be able to attend any.
     
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  18. trishrhymes

    trishrhymes Senior Member

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    That's what the FINE trial was for - people who were housebound and unable to go to a clinic. They had home visits instead. It was a null trial, so never gets mentioned by the BPS/CBT/GET fanatics.
     
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  19. Barry53

    Barry53 Senior Member

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    Ah ... no big surprise there then.
     
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  20. Barry53

    Barry53 Senior Member

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    Not arguing it is anything like 100% valid, just that it must be significantly less subjective than questionnaires, which I doubt are really worth a light to assess real physical capability, albeit probably some use in assessing a person's perceptions of their physical ability, providing the results are not presumed to have a particularly linear characteristic.
     
    Last edited: Jul 7, 2017
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