Graded exercise therapy for ME/CFS is not effective and unsafe. Re-analysis of a Cochrane review (2018) Health Psychology / Vink

Process in the event of serious errors in published Cochrane Reviews
https://community.cochrane.org/edit...ent-serious-errors-published-cochrane-reviews

 

Definitely agree, I’ve been wondering whether to say something, but figured it’s probably too late to change once it’s published. It is something that should have been discussed with the author by the publishers or reviewers. Thankfully the paper is clear even though the title isn’t.

 

https://twitter.com/user/status/1050674821531484161

 

https://twitter.com/user/status/1053052724428836864

https://twitter.com/user/status/1053059552235675654

 

While it doesn't mention some of the specific points I made/issues I raised, it does mention others, including many of the specific citations I used.

But I don't make any money from writing papers, comments and the like so I'm quite happy to see them being used for the cause. And a number of my own ideas over the years have been picked up from other publications and discussions on forums.

Also, he does cite some of my publications and in other cases it works better to cite the original source rather than my publications.

Mark does brilliantly to write these papers, despite his severe impairments. I'm very grateful to him for doing so. Thanks also to Alexandra Vink-Niese for her contribution. I am not familiar with any other work of hers on ME/CFS.

 

I thought this was very good. However, I just thought I would also highlight some minor points I was not convinced about.

I've come across very few CFS studies which completely exclude people with psychiatric comorbidities such as depression (except major depressive disorder) and anxiety, though some stratify the samples in some or all of the analyses. No harm raising the issue, but just to say that the review is not different to most studies in including some people who also had mental health issues.

 

Not an error but 24 here is equivalent to 70 on the 0-100 physical functioning subscale (that is not normalised)

 

Just to point out actual data in the trial:

So 77.6% weren't necessarily working. Some people could be in a bit of a grey area, e.g. work in the home.

 

Yes, objective outcomes are very important in open-label trials like this. As well as using two subjective outcome measures has to primary outcomes, they also reported on lots and lots of other subjective outcome measures as secondary outcome measures.

The only objective outcome measure they reported on was health resource use for which they presented follow‐up data from one trial.

 

This can give the impression that there was an improvement in the step test results, but there wasn't.

It might have been more interesting to refer to the figure for the 6-minute walk test where there was a statistically significant improvement for the graded exercise therapy group, but there was missing data for 31%.

 

That is true. Researchers sometimes mention this figure of 30 minutes, 5 days a week, and this gets mentioned when describing the programme. But it's not clear that many, or even any participants actually did this amount of exercise so such a goal would necessarily exclude the relevant population.

I remember Peter White said somewhere that the figure of 30 minutes 5 days a week was chosen because that is the figure in guidelines for the whole population in the UK. However, it is very questionable to suggest this for people with an unusual response to exercise. I think exercising every second day, while missing some days if necessary, is possibly the most suitable program. I remember reading somewhere that after two days without exercise you start losing fitness.

 

Seems like a good point.

 

Just to point out that while the threshold of less than 83.3 is certainly very high, there were a lot of other criteria also:

 

Yes, it seems interesting.

From the full Wearden et al, 1998 paper

 

I would be careful about quoting the figure of 4 or more with regard to Likert scoring i.e. 0-42.

With the 11-item version, healthy people score an average around 11 which is the 11 items, where people on average, said "No more than usual" which scores one. "0" is for "Less than usual". So 4+ would be a ridiculous cut-off point.
Presumably the 4+ threshold refers to bimodal scoring i.e. where the total score is 0-14. Nowadays only 11 items are usually used and the threshold is 4 or more on bimodal scoring.

The Wearden et al paper itself probably uses both bimodal scoring and Likert scoring but doesn't look like it makes it clear when it is using each one

 

I checked this and it is true, though the baseline mean was 16.0.

24 is equivalent to 70 on the 0-100 scale, 25, is equivalent to 75 on the 0-100 scale and 16 is equivalent to 30 on the 0-100 scale.

 

Yes indeed:

 

Exactly. The core failure of the review is in not exposing the failings of the studies under review. So by exposing the studies' failings (yet again!), the review's core failure is also exposed (again!).

 

Thanks for all those notes Dolphin. I struggle to remember the details of just PACE, nevermind all those other trials too.