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PACE trial claims of recovery are not justified by the data: A Rejoinder to Sharpe et al.

Esther12

Esther12

Senior Member
Messages
13,774
The data from the PACE trial is so damn helpful. It just shows how valuable data sharing is for furthering scientific debate. (I spent some time coming up with an anaology of a card game where one side gets the whole deck, but then selects cards that can be used by either side... it was not as illuminating as I'd hoped).

Both my favourite parts of this response stem from taking Sharpe's points seriously and then saying 'well lets look at the data then...'

For example, the definition of recovery used in the studies
by Deale et al. [8] and Knoop et al. [9] were a lot stricter than
the revised criteria used in PACE. If the Deale et al. recovery
criteria are applied to the PACE data, for example (it is
possible to use three of the four criteria), the PACE recovery
rates fall to a maximum of 9% for CBT, which is very
different from the 24% for CBT cited in Deale et al.
Click to expand...


Sharpe et al. [3] challenge our conclusion
that none of the “recovered” patients achieved
normal walking distance in the six minute walking
test. They argue that the norms we used were
inappropriate, because they were obtained from a
version of the task that included periodic verbal
encouragement (“you’re doing well” or “keep up
the good work” every minute, as specified in the
American Thoracic guidelines [12]) whereas
PACE’s version did not. However, a recent large
study that investigated the effect of standard verbal
encouragement in this test did not find it to have a
significant effect on distance walked. [13] Further,
even if we reduce our lower bound for normal
performance considerably (by, say 31m, which is
the largest difference that has ever been attributed
to encouragement in any study, including non-
standard administrations [14]), only two patients
who counted as recovered by the original protocol-
specified definition achieved this new shorter
distance, and both were in the group that received
the comparison treatment, Adaptive Pacing
Therapy.3 None of the CBT or GET patients
achieved this threshold.
Click to expand...

Lovely.
 
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A.B.

A.B.

Senior Member
Messages
3,780
Nice article. Did you consider pointing out that the subjective "improvement", which is all that's left in favor of the treatment, is comparable to the strength of a psychological placebo intervention as found by Wessely et. al. in a review on the topic?

So this treatment really appears to be completely useless. It's ironic that Wessely himself would provide the proverbial final nail in the coffin.

If you considered pointing this out, can you explain why it was ultimately not done? Is it because ultimately it boils down to belief (in whether a placebo effect is useful or useless despite not leading to objective improvement)?
 
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T

Tom Kindlon

Senior Member
Messages
1,734
A.B. said:
Nice article. Did you consider pointing out that the subjective "improvement", which is all that's left in favor of the treatment, is comparable to the strength of a psychological placebo intervention as found by Wessely et. al. in a review on the topic?

So this treatment really appears to be completely useless. It's ironic that Wessely himself would provide the proverbial final nail in the coffin.

If you considered pointing this out, can you explain why it was ultimately not done? Is it because ultimately it boils down to belief (in whether a placebo effect is useful or useless despite not leading to objective improvement)?
Click to expand...
The original paper and this rejoinder are on recovery. One of the reviewers directed us away from talking about efficacy in general.

However our original recovery paper does talk about subjective and objective measures.

It was argued that this rejoinder should be short or it wouldn't be read so it doesn't include all the possible points.
 
anciendaze

anciendaze

Senior Member
Messages
1,841
This is a question for those who have gone through the entire bulk of PACE literature repeatedly, something I no longer have the stomach to do. Did the protocol used at the time the PACE trial was funded make any mention of possible discordant results between subjective data collected by questionnaire and objective data on physical performance, aside from making objective data secondary so it could be ignored if inconvenient?

There should now be no question that such a result took place w.r.t. CBT, where neither the "step test" nor the six-minute walk test showed any improvement. This alone implies that either the hypothesis of psychological causation was falsified, or that CBT was completely ineffective w.r.t. improving objective performance.

When it comes to GET and the six-minute walk test there is a problem with the data because about 1/3 of people counted as participants declined to participate in that test either before or after treatment. Dropping those who did not fully participant is not an acceptable correction because it introduces a new post facto selection effect in a study which already shows a huge prior selection in the reduction from 3158 to 640. That raises questions about the applicability of any claimed benefits to the public health problem for which the study was funded. We seem to be arguing about whether anyone in a cohort of 3158 referred by NHS GP/PCP doctors might benefit from CBT or GET, with no data at all on the effect of the recommended combination CBT+GET. This is a clear indication of the triumph of authors opinion over data.

Rather than arguing over what they actually demonstrated I'd like to know what on Earth they believe you demonstrate by showing that a few people out of a huge cohort might or might not benefit from the favored interventions -- in the opinion of certain authors. We are literally at the level of anecdotal evidence following a substantial expenditure in a field where research funding is tight.

No such problem exists with "step test" data, which conclusively shows no improvement over standard medical care. This is a discordant result, and so far as I can tell, the authors went to some lengths to ignore it.

Most respectable scientific research considers discordant results especially important in the discussion section. Often it leads to modification of the initial hypothesis. These authors seem incapable of changing their own beliefs because of data.
 
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