Patterns of daytime physical activity in patients with chronic fatigue syndrome, 2020, Chalder, Sharpe, White et al

Tom Kindlon said:
There is no control group.

Here are some research studies that found no difference in variations in activity patterns when a control group was used:
"The heterogeneity in the physical activity pattern between subjects within the CFS and control group did not differ." https://pubmed.ncbi.nlm.nih.gov/21843746/

"There is no difference in variation of physical activity levels between patients with chronic fatigue syndrome and healthy control subjects" https://pubmed.ncbi.nlm.nih.gov/20943713/

"No between-group differences were found in the pattern or amount of sleep, activity, or cortisol secretion."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079947/

"the present study was not able to confirm the hypothesis of a more fluctuating activity pattern in patients with CFS, nor during the day, nor during the registration period." https://www.sciencedirect.com/science/article/abs/pii/S0003999311004175

"there were no significant group, gender or interaction effects for the number of absolute large or relatively large day-to-day fluctuations (Table 2 and Table 3)." https://pubmed.ncbi.nlm.nih.gov/11164063/
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Isn't this one of the reasons you do not do post hoc analyses? If you've not stated beforehand what you intend to do, then if not careful can find all manner of supposedly meaningful patterns in the data that can fit the bias of choice?
 
https://en.wikipedia.org/wiki/Post_hoc_analysis
Wikipedia said:
... journal editors demanded that the statistician Richard Peto provide a post hoc analysis of subgroups for the use of aspirin as secondary prevention for people who had experienced heart attacks. He refused the request as being statistically unsound and likely to lead to nonsensical results. When they persisted, he provided the editors with a subgroup analysis that evaluated the supposed response based upon the patients' astrological signs.
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Basically once you've had the chance to root around in the data, over and over in all manner of different ways, the odds are you will home in on some apparent pattern that seems to support whatever argument you choose to promote. Hence:
Wikipedia said:
... the US Food and Drug Administration does not accept post hoc analysis
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http://unbiasedresearch.blogspot.com/2017/04/pre-hoc-vs-post-hoc-analysis-whats.html

upload_2020-5-30_12-9-1.png
When conclusions are made from post-hoc analyses, there is an inherent bias, as we are able to test the data in any way that produces a favorable result. In many cases, this leads to data dredging or in the worst cases, p-hacking.

...

The one real benefit of post-hoc analyses is that they have the capacity to show patterns in the data that were not the primary objective of the study. This can be especially beneficial for exploratory science. The only caveat is that conclusions should not be made from post-hoc analyses, only hypotheses which can be further tested in a separate experiment.
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[my highlighting]
 
@JohnTheJack would it be worth considering a further FOI request for the remaining PACE data, anonymised of course? This latest endeavour of the PACE authors clearly undermines an objection they might seek to resurrect - that they no longer have access to a statistician for the PACE data.

If so then would have to take into account (discussed elsewhere in S4ME), that any new data must include adequate keys to be able to unambiguously synchronise it with previously acquired data. Or better still, just ask for the whole anonymised set anyway?
 
Barry said:
@JohnTheJack would it be worth considering a further FOI request for the remaining PACE data, anonymised of course? This latest endeavour of the PACE authors clearly undermines an objection they might seek to resurrect - that they no longer have access to a statistician for the PACE data.

If so then would have to take into account (discussed elsewhere in S4ME), that any new data must include adequate keys to be able to unambiguously synchronise it with previously acquired data. Or better still, just ask for the whole anonymised set anyway?
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Uh. Good catch. Another lie exposed, again. Official lie, even.
 
Snowdrop said:
Is this the final paper to be expected from this trial (i have a dim memory of FoI requests being denied because further papers were still to be written on the trial)?

Was this paper expected or have the authors decided to publish all out of the blue?
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Just read this paper.Incredulous that it was published until I saw the comment about the editorial board of the journal.

The paper states the following, suggesting that PACE is going to keep "giving" into its second decade.
"It may be that the physically inactive group improve by doing more, the physically active group by doing less, and the boom and bust group by stabilising their activity with no consequent change in overall activity levels. This hypothesis requires testing. Whether these sub-groups do predict treatment outcome will be assessed in a future paper."
​
 
MSEsperanza said:
Two of the authors (Sharpe & White) are on the journal's editorial board:

https://www.sciencedirect.com/journal/journal-of-psychosomatic-research/about/editorial-board
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Good spot. Probably explains why my recent letter to the journal was rejected
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:-)
 
rvallee said:
Selective reporting of data is not an acceptable practice. The plan was to measure activity at the beginning and end of the trial, not do some BS analysis trying to cherry-pick random correlations from only one initial measure. This is infantile in its incompetence. Mythbusters were more rigorous in their experiments.
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That was the plan at the start of the trial. By the time the protocol was published they'd dropped actometers as an outcome measure, and they don't have the data needed to publish according to the original plan. I'm not sure that's really selective reporting?
 
Ravn said:
There've been some who have likened our exercise intolerance to the sort of allergy that you treat with desensitisation therapy - so GET would be a sort of desensitisation therapy for us.
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In my understanding one should well elevate central sensitation this way, at least this should be the possibility when central sensitation is too strong, I would mathematically guess.
 
Joan Crawford said:
OMG this is just shocking: "Gradually increasing the intensity of your exercise over time may help reduce your hypersensitivity to exercise, just like allergy shots gradually reduce a person's hypersensitivity to a particular allergen." WTF...............
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Didn't work for me, I tried allergy shots for 2 years and I still sneeze when the hazel's out. It was bugger all use. So it would be quite a fair analogy actually, except that allergy shots rarely leave people wheelchair bound and unable to tolerate light or sound.
 
Joan Crawford said:
OMG this is just shocking: "Gradually increasing the intensity of your exercise over time may help reduce your hypersensitivity to exercise, just like allergy shots gradually reduce a person's hypersensitivity to a particular allergen." WTF...............
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Reminds me of the glucose analogy that a certain someone likes to mention occasionally...
 
Is that paper one of the PACE trial investigators' attempts at convincing clinicians that BPS research on ME/CFS is able to generate reliable evidence?

(I'm actually searching for another reference: If I remember correctly, in one of the PACE trial papers the authors concluded that they found no evidence of significant differences between subgroups with different diagnostic criteria. I don't remember whether one of these diagnostic criteria included PEM though. [???] )
 
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