Cochrane Review: 'Exercise therapy for chronic fatigue syndrome' 2017, Larun et al. - Recent developments, 2018-19

Thank you, and especially to @Marit @memhj for getting hold of them. I have now had a chance to read these emails and they are horribly fascinating. And of course completely missing the point about the folly of relying on subjective outcomes in a review of unblinded trials, because of course that would necessitate starting the review again. So the nitpicky argument over the "defensible" way to describe the size of an effect is a waste of everyone's time, as we all know. Sole concern of both sides is to save face rather than help people with ME.

 

The most bizarre thing is their grading of the evidence. HADS they score "very low", but the combined fatigue measures (which they should have realised that they can't combine, because one (CFQ) measures *change* in individual fatigue since becoming ill and the other (CIS) measures pseudoabsolute individual fatigue over past 2 weeks) are scored "low" or "moderate" depending on which likert/non-likert version they used. It seems to indicate that their GRADE score is dependent on whether the score provides a significant result in the review, and not on whether it is of sufficient *quality* and suitability to do so.

If HADS scores "very low", then all the scales should score "very low", because they all suffer from the same problems.

 

I can't remember that part of the discussion now, but could it be that they had fewer trials with HADS as an outcome, and that affected the rating? On the assumption that the more garbage you get in the better?

 

[my bold]

How can a scientific paper include the above? Are they suggesting that adverse safety events would not constitute worsening of symptoms? You just cannot make a concrete assertion like "did not" if in the next sentence saying you had insufficient information to draw firm conclusions! This is like dealing with shape shifters. I really do worry that these people see worsening of symptoms as completely divorced from harms, whereas surely they are all on a common spectrum of outcomes, from being a little bit worse, all the way through to being dead, and everything in between.

 

Oh - I thought it was that the change resulting from treatment (so requiring a control group comparison) was substantial enough to mean the treatment was seen as worthwhile. If it's not assessed on the basis of a difference between arms then isn't that more worrying?

Thinking back, that PACE researchers gave the % for their MCID per arm, not on the basis of a difference between arms. I'm going to be annoyed with myself if I've ben reading MCID papers while having forgotten exactly how MCID is used!

This seems another one of those problems that is so commonplace in medical research that we're unlikely to be able to make much progress with it.

 

Sounds like I misunderstood you... I'm not feeling up to understanding things in this heat!

 

And how can the Cochrane GET review claim no worsening of symptoms while the AHRQ concluded the following about harms from GET using essentially the same evidence.

"GET was associated with higher numbers of reported adverse events compared with counseling therapies or controls. Harms were generally inadequately reported across trials."

"Harms were not well reported, although in one trial patients receiving GET reported more adverse events compared with those receiving cognitive behavior therapy (CBT), adaptive pacing, or usual care; one trial reported more withdrawals of patients receiving GET, one trial had a high percentage of patients refusing repeat exercise testing, and several other trials reported more withdrawals of patients receiving GET, all compared with controls."​

 

Well, it is an attack on the credibility of science. Imagine if this dumbing down spread through all of medicine. It's a genuine slippery slope that could end up downgrading the value and effectiveness of all medical practice, including "respectable" diseases.

 

And if patients did report harm woud they be believed or would it be dismissed/downplayed as part of their wrong illness beliefs?

 

They simply have no idea what they're talking about. Somehow that's waived off, as if they could not possibly be mistaken but that is the core issue here, they are completely out of their depth and insist it is the patients who are confused about our own illness, that it's reality that is wrong, not their personal interpretation of it.

 

Given it is based on being smallest change in clinical outcome deemed to be important, then I presume it would be valid to compare the difference between a control arm having no intervention, and a trial arm with the intervention; the difference measured would be the same as the 'D' in MCID wouldn't it?.

ETA: I see you resolved this a bit later.

 

Especially arbitrary scales. Neither of HADS, SF-36 or CFQ are of much relevance to ME, in combination or in isolation. Their choice is nothing more than a matter of preference, they are not validated or adequate for this purpose, especially when objective measures are possible, like working days, physical fitness, etc.

There is a lot of discussion over precision points for a scale that is as inaccurate as a scale can possibly get. It's exactly as precise as measuring integer values of people's height in football fields. One can argue for days about how significant the scoring either of 0 or 1 is, it does not make it a meaningful measurement anymore than measuring heat with adverbs because someone finds celsius too cumbersome or that farenheit is scary or something.

 

We know the answer to that. The logic over the safety of those treatments is entirely circular. They are safe because there are no reports of harm and it is not possible to report harm because they are known to be safe. The trials did not do due diligence and neither is the implementation of those treatments in practice, which we have now confirmed.

 

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