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Cochrane Review (2008/2009): CBT for CFS in adults

Bob

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Cognitive behaviour therapy for chronic fatigue syndrome in adults.
Jonathan R Price, Edward Mitchell, Elizabeth Tidy, Vivien Hunot
Published Online: 15 APR 2009
DOI: 10.1002/14651858.CD001027.pub2

Cochrane Database of Systematic Reviews 2008, Issue 3. Art. No.: CD001027.
Publication status and date: Edited (no change to conclusions), published in Issue 2, 2009.

http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD001027.pub2/abstract



Summary of main conclusions (based on subjective measures):

Fatigue severity. CBT vs usual care. Post treatment.
Post treatment, the Standard Mean Difference, between CBT and usual care, was -0.39, in favour of CBT.
Five traditional CBT studies and one mindfulness/compassion-focused CBT study (373 participants in total) contributed to this outcome. The difference in fatigue mean scores between the CBT group and usual care group was highly significant in favour of the CBT group (SMD -0.39, 95% CI -.0.60 to -0.19). No statistical heterogeneity was indicated.

Clinical response rate. CBT vs usual care. Post treatment.
Post treatment, an extra 14% of patients responded to CBT, compared to usual care, when using subjective measures.
Four studies (371 participants) contributed to this outcome. A total of 40% of participants in the CBT group showed clinical response to treatment, in contrast with 26% in the treatment as usual care group. The difference between the two groups was highly significant (OR 0.47, 95% CI 0.29 to 0.76). No statistical heterogeneity was indicated.

Follow up.
"Findings at follow-up were inconsistent."
"Findings at follow-up were heterogeneous and inconsistent."
"At follow-up, 1-7 months after treatment ended, people who had completed their course of CBT continued to have lower fatigue levels, but when including people who had dropped out of treatment, there was no difference between CBT and usual care"

CBT vs other psychological therapies.
There's also a comparison of "CBT versus other psychological therapies, comprising relaxation, counselling and education/support (four studies, 313 participants), the difference in fatigue mean scores at post-treatment favoured CBT (SMD -0.43, 95% CI -0.65 to -0.20)."
However, "At short term follow-up, the difference between CBT and other psychological therapies was inconsistent, and statistical heterogeneity was indicated."


Interesting secondary outcomes ('No significant differences'):

1) Improvement in physical functioning. Post treatment.
Three traditional CBT studies and one mindfulness/compassion-focused CBT study (318 participants in total) contributed to this outcome. Measures used to assess physical functioning comprised Karnofsky performance status scale (one study) and SF-36 physical functioning subscale (three studies). The difference in physical functioning mean scores between the CBT group and the usual care group was not significant (SMD 0.11, 95%CI -0.32 to 0.54). Significant heterogeneity was indicated (I2 = 68%) and a random effects model was used.

5) Improvement in quality of life. Post treatment.
One traditional CBT study (184 participants) contributed to this outcome. The measure used to assess improvement in quality of life comprised the Euro-Qol. The difference in QoL improvement rates between the CBT group and the usual care group was not significant (OR 1.19, 95%CI 0.58 to 2.46).

7) Adverse effects
No studies contributed to this outcome at post treatment or follow-up.


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Bob

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England (south coast)
Hi folks.

I only recently came across the 2008/2009 Cochrane meta analysis review of CBT for CFS.
I've searched through the forum, and I can't find a thread about it.
So I thought I'd post the main conclusions in a new thread.

Interestingly, the results seem (superficially) extraordinarily similar to the PACE Trial.
But this might be misleading, because the results are only similar if the measures of success, and the endpoint thresholds, are similar. (i.e. it depends on what level of improvement was used to indicate a positive outcome or a response to treatment, and exactly which scales were used.)
I haven't dug deep enough yet to see what measures of success they used in all the reviewed papers.

The Cochrane review was pre-PACE & FINE Trial publication.

The main results/conclusions are based on subjective measures.
 

Bob

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Location
England (south coast)
Cochrane Review said:
1) Reduction in fatigue severity. Post treatment.
Five traditional CBT studies and one mindfulness/compassion-focused CBT study (373 participants in total) contributed to this outcome. The difference in fatigue mean scores between the CBT group and usual care group was highly significant in favour of the CBT group (SMD -0.39, 95% CI -.0.60 to -0.19). No statistical heterogeneity was indicated.

Can anyone help me interpret this please?
The Standard Mean Difference is given as -0.39.
Would this commonly be considered as borderline small/moderate effect size? i.e. just less than 'moderately effective'?
Or have I wrongly conflated SMD with Cohen's D?
 
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jimells

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"Clinical response" : I had a "response" to therapy -- I fired the therapist! Would that have counted in the study? ;)

So there's no improvement in physical functioning, and there's no improvement in quality of life. How could these be 'secondary endpoints'? If I feel slightly less tired, but I still can't do anything, then really, what's the point? It seems to me, without actually reading the review, that the reviewers have little understanding of the illness. Big surprise, eh?
 

Bob

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Location
England (south coast)
"Clinical response" : I had a "response" to therapy -- I fired the therapist! Would that have counted in the study? ;)

So there's no improvement in physical functioning, and there's no improvement in quality of life. How could these be 'secondary endpoints'? If I feel slightly less tired, but I still can't do anything, then really, what's the point? It seems to me, without actually reading the review, that the reviewers have little understanding of the illness. Big surprise, eh?

Hi jimells, I think you've just summed it all up perfectly, in one short paragraph! :)
 
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I'm sure this has been discussed before, but maybe not in it's own thread? Thanks for the summary anyway.
 

Bob

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I'm sure this has been discussed before, but maybe not in it's own thread? Thanks for the summary anyway.

Yep, I thought it must have been discussed somewhere, but I couldn't find any posts about this specific Cochrane review, and there doesn't seem to be a dedicated thread. I'd not come across this paper until recently.
 

Bob

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Just been having another look at the 2008 Cochrane review.

It's interesting that at medium-term and long-term follow-up, results were 'inconclusive', which I suppose means not proven to be effective. Medium-term was defined as 7-12 months post-treatment, and long-term is defined as more than 12 months.

The benefits of CBT in sustaining clinical response and reduction of fatigue symptoms at short and medium term follow-up are inconclusive.

The benefits of CBT in improving physical functioning and reducing depression, anxiety and psychological distress at post treatment and at follow-up are also uncertain.

Cognitive behavioural therapy versus usual care
...
...at short to medium term follow-up (rather than immediately post-treatment), the evidence for the effectiveness of CBT was inconclusive.
 
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Bob

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England (south coast)
If anyone can shed any light on this, then I'd be grateful.

I'm interested in the results comparing CBT to a waiting-list control.
The Cochrane review's discussion in relation to waiting-list controls is contradictory.

The 'plain language summary' says that CBT was more effective than the waiting list, but the rest of the text says that CBT was no more effective than the waiting list. I wonder if it's a mistake in the 'plain language summary'.

I've been finding it difficult to drill down into the data to get the facts. (There's so much data!)

And I'm not certain if they are comparing post-treatment CBT with the waiting list control, before or after the waiting-list participants had also received CBT.

Plain Language Summary
...
The review showed that people attending for CBT were more likely to have reduced fatigue symptoms at the end of treatment than people who received usual care or were on a waiting list for therapy, with 40% of people in the CBT group showing clinical improvement, in contrast with 26% in usual care.

Treatment as usual vs waiting list (Graph 05 02)
Three studies used a treatment as usual condition and three studies
used a waiting list as the control condition. A highly significant
difference in effect was shown for the CBT group when compared
with treatment as usual. In contrast a non-significant difference
in effect was shown for the CBT group when compared with the
waiting list condition
.

Cognitive behavioural therapy versus usual care
...
...in contrast, there was no significant difference between CBT and waiting list control.

Waiting list is frequently employed as an ethical ’no treatment’ condition, to ensure that all participants eventually receive the ’active’ treatment. This approach was used in almost half of all studies comparing CBT against usual care. However, sub-group analyses showed that, at post-treatment, waiting list patients had reduced fatigue symptoms equivalent to those of patients attending for treatment. A possible explanation is that being on the waiting
list for treatment had a ’holding’ positive influence, decreasing the apparent effect of the CBT intervention.
 

Cheshire

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Is there in the literature one study that shows a significant and lasting effect of CBT for ME/CFS? (I do not even ask based on objective datas...) Or do the CBT defenders rely only on trials of that kind to justify the harm they're doing???
 
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I wasn't clear on this either. Sorry - I started looking, and had to give up. I'm going to keep going with this, but it might take me a long time to get anywhere.

OT they did say this:

Blinding
One trial (O'Dowd 2000) stated that "both the participants and those administering the assessments were unaware of which cohort the subject was in", and indeed described its protocol as a "double-blind randomised controlled trial".

I'm not really clear how that works for a trial like that? That was one that was a null result according to primary outcome measure, but that had other positive things they could point to:

http://forums.phoenixrising.me/inde...rct-of-group-programme-odowd-et-al-200.29241/

They also mention other trials that used blinded assessment for the Karnofsky scale that I'd not read about.
 

Bob

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An interesting aside, that Keith Laws just Tweeted.
It's a discussion about how different controls, employed in psychotherapy trials, may lead to different effect sizes.

Waiting list may be a nocebo condition in psychotherapy trials: a contribution from network meta-analysis.
Acta Psychiatr Scand. 2014 Apr 4. doi: 10.1111/acps.12275. [Epub ahead of print]
Furukawa TA, Noma H, Caldwell DM, Honyashiki M, Shinohara K, Imai H, Chen P, Hunot V, Churchill R.

http://onlinelibrary.wiley.com/doi/10.1111/acps.12275/abstract


Wikipedia's explanation of a 'nocebo' (it's the opposite of a placebo):
In medicine, a nocebo (Latin for "I shall harm") is a harmless substance that creates harmful effects in a patient who takes it. The nocebo effect is the negative reaction experienced by a patient who receives a nocebo.
http://en.wikipedia.org/wiki/Nocebo
 
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It doesn't seem clear (from just the abstract - can't access the paper) whether they're talking about a 'real' nocebo - ie it actually makes health worse, or just that it leads to people reporting symptoms more negatively. I can certainly think of control interventions which would seem to piss patients off and make them want to report their symptoms more negatively, and a waiting list control could be pretty irritating.
 

Bob

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Location
England (south coast)
More contradictions, or ambiguous wording, re physical function...

"Physical functioning, depression, anxiety and psychological distress symptoms were also more reduced when compared with other psychological therapies."

"The benefits of CBT in improving physical functioning and reducing depression, anxiety and psychological distress at post treatment and at follow-up are also uncertain."

"The difference in physical functioning mean scores between the CBT group and the usual care group was not significant (SMD 0.11, 95%CI -0.32 to 0.54)."
 
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Bob

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England (south coast)
I'm struggling to make sense of this Cochrane paper. Partly because there are so many sections, and so much data, and also because I'm beginning to think it hasn't been summarised helpfully. I think the summaries have placed an unhelpful gloss on CBT by discussing 'improvement' where there was no clinically significant improvement etc.

Digging down into the actual data will be a nightmare, which is why I've been avoiding it so far.

I also need to revise my understanding of Standard Mean Differences and how they relate to effect size. The reported SMDs are essential to interpreting the outcomes.

(I wonder if @biophile has seen this thread yet? You're quite familiar with the paper, aren't you bio?)
 

Bob

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I'm beginning to think that the discussion in this Cochrane paper is all smoke and mirrors, with the intention of placing a positive spin on the actual results! (Why should I be surprised?) (But it is making me quite annoyed.)

Every time I read that there was an improvement after CBT, it turns out that either it was a non-significant improvement, or that there was no significant improvement at short-term follow-up (i.e. 1 month) or medium-term follow up etc. And, of course, all this is without robust or standardised control groups.

One example of this is in my post, two posts above. Physical function is first described as improving after treatment with CBT, but then it turns out that it was a non-significant and 'uncertain' improvement.

And these are two more examples of how the effects disappear when you dig deeper, but there are many examples of this:

"...at short to medium term follow-up (rather than immediately post-treatment), the evidence for the effectiveness of CBT was inconclusive."

"At short term follow-up, the difference between CBT and other psychological therapies was inconsistent, and statistical heterogeneity was indicated."
 
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biophile

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@Bob . I agree that the paper is poorly laid out and the data is from a messy hodgepodge of small trials.

Re physical function etc, I think you are confusing [CBT vs usual care] with [CBT vs other psychological therapies]. The former comparison shows no statistically significant difference but the latter comparison does.

Re the waiting list control sub-group analysis, the wording is ambiguous in areas, but waiting list controls are common in trials, so I doubt they are comparing [post-CBT straight away] to [post-CBT after waiting first], what purpose would that serve? There is no other indication that this was done, and I think this paragraph explains it:

Waiting list is frequently employed as an ethical 'no treatment' condition, to ensure that all participants eventually receive the ’active’ treatment. This approach was used in almost half of all studies comparing CBT against usual care. However, sub-group analyses showed that, at post-treatment, waiting list patients had reduced fatigue symptoms equivalent to those of patients attending for treatment. A possible explanation is that being on the waiting list for treatment had a ’holding’ positive influence, decreasing the apparent effect of the CBT intervention.

When the waiting list control group eventually get CBT, that usually occurs after the trial study period is over. Here, "post-treatment" refers to the timepoint in the trial when the active CBT group completed therapy.

Re the problem where the plain language summary appears to state that CBT is effective vs waiting list control, but later in the paper it states the opposite. The main analysis of "CBT vs usual care" pooled together studies which used either usual care or waiting list controls, whereas the relevant sub-group analysis referred to later only included waiting list controls:

Main comparisons

1. CBT versus usual care (to include treatment as usual and waiting list).

Subgroup analysis and investigation of heterogeneity

1) Type of control condition (minimal management/standard care vs waiting list).

The review showed that people attending for CBT were more likely to have reduced fatigue symptoms at the end of treatment than people who received usual care or were on a waiting list for therapy, with 40% of people in the CBT group showing clinical improvement, in contrast with 26% in usual care.

Re standardized mean differences, the key to understanding SMD is understanding the standard deviation.

http://en.wikipedia.org/wiki/Standard_deviation

SMD is calculated as the difference between two means (the averages of two groups) divided by the standard deviation for the data in question. There are a few different ways for calculating and inputing the SD.

http://en.wikipedia.org/wiki/Effect_size

The interpretation of SMD is too arbitrary.
 
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biophile

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@Esther12 re blinding in the study by O'Dowd et al (2006).

Blinding/masking

Both the participants and those administering the assessments were unaware of which cohort the subject was in. It was not possible to mask participants in the SMC group for obvious reasons. The assessors were instructed not to enquire about any treatment undertaken as part of the trial and to stop the subject from making any reference to the trial during the course of the reassessments. The assessor was not present during the intervention period.

The success of the blinding/masking was not formally assessed. However, it was observed that the EAS group spoke in terms of this being a valid and plausible treatment approach. The therapists involved in the delivery noted that many of the key concepts presented in the CBT group were spontaneously raised by EAS members.

http://www.journalslibrary.nihr.ac.uk/hta/volume-10/issue-37

However, a 2012 systematic review indicates that there was only provider blinding but not assessor blinding or patient blinding. Maybe that is a mistake, or they took a conservative view because there was no formal testing of blinding?

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2362.2012.02701.x/full

As you said, the Cochrane systematic review discusses the blinding status for other studies. Adequate blinding of CBT and GET would be difficult, and the placebo response or reporting/response biases could be introduced by other means than merely knowing which hyped therapy they have been allocated to, such as accepting the rationale of (unlabeled) CBT/GET.
 
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Bob

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@biophile
Wow, you've managed to make some sense of it all! I've no idea how you managed that without poring over it for days!
What you've said all fits with my own interpretation, now that you've explained a few things for me.
Great work! Thanks very much for that :thumbsup: