2025: The 2019/24 Cochrane Larun review Exercise Therapy for CFS - including IAG, campaign, petition, comments and articles

I agree. I was talking about least worst options not ideal options.

The ideal, as far as I'm concerned, would have been to do a proper update with correct methodology which would have found exercise useless and potentially harmful for anyone with chronic fatigue, including ME/CFS.

And Cochrane recognising the stuff about unblinded trials and subective outcomes publicly and withdrawing a whole swathe of other reviews.

 

While we are taught about double blind, the cop-out when not being able to blind the participant is the same as the BPS are using: "It's difficult" and left at that. Nothing about how using objective outcomes could reduce the issue, or that subjective outcomes would be an additional issue. And since everyone is doing it then it must be fine.

 

When collecting diet intake data in large studies, we are supposed to validate using a method with different bias. In practice food frequency intake questionnaires are used and then "validated" by performing a diet intake interview with a selection of the participants (both have similar biases like recall and reporting bias). If they are validated at all. A few use double-labelled water and that can validate energy intake but it's difficult to do at scale.

I seem to recall a table with "rules" in Norwegian, but I can't find it again but as I recall it was like this for when something is seen as reliable:
Two large cohort studies that point in the same direction
One cohort study can be exchanged by five case-control studies

These studies can have the same biases so the rules don't work, but here we are.

 

I don't want you thinking we are dismissing this risk. It is a true risk. It is possible that a Fukuda cohort has no people with PEM in it. But, look at the Fukuda criteria. You aren't just picking up people with chronic tiredness, they have to have other things going on too, and they may have PEM lasting 24 hours as one of the required four extra symptoms. I think the risk of a Fukuda cohort not having people with PEM in it is quite low; requiring results to be replicated from multiple studies can help to cover that risk.

Yes, making a selection criteria for a trial as precise as possible is important. I don't think anyone here is saying that using the Fukuda criteria is a good thing, and the problems get even worse when researchers use less restrictive versions of Fukuda. We do want to see studies trying to ensure that people labelled as having ME/CFS all do report PEM.

But. As Jonathan said, the BPS studies on GET, even using the Fukuda criteria, even with their subjective outcomes and lack of blinding, even with all the other various flaws, have pretty much failed to find any clinically relevant benefit. For anyone. Reported benefits slosh around in the range that is entirely compatible with a placebo treatment.

Focusing on the issue of the diagnostic criteria distracts from this main message of studies with a very high risk of bias and small to very small reported benefits that cannot be differentiated from placebo responses.

 

I so do not understand where Trisha Greenhalgh is on this. I haven't been following closely but she seemed to be prejudiced against people with ME/CFS, blocking reasonable people on Twitter. But argues against people with Long Covid being subject to BPS ideas? And now she is retweeting Jacqui Wise's good article in the BMJ that is supportive of people with ME/CFS?

Perhaps it doesn't really matter what she thinks, although she seems to pop up in various influential places. But, does anyone understand what is going on there?

 

I think those horribly flawed studies can still tell us something though. If you can bias your study so badly in favour of finding a positive result, and, at the end of it you still can't show that exercise therapy provides a benefit for people with chronic fatigue above a level easily achieved with a placebo, that is useful information.