3:43 p.m.
February 24, 2011
IACFS/ME Statement on the PACE Trial:
The Issue of Illness “Reversal”
The much publicized UK-based PACE trial (Lancet, Feb. 18th;
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(11)60096-2...)
reported positive outcomes for patients with CFS/ME who were treated with
cognitive-behavior therapy (CBT) or graded exercise therapy (GET) in comparison to a
standard medical care condition or an adaptive pacing condition. The adaptive pacing
condition was intended to help patients adjust their activity levels according to their
available energy (based on envelope theory). The findings were similar to previous CBT
and GET studies in CFS. This trial was unique in incorporating a pacing condition and
recruiting a very large sample.
We certainly support any effective treatment for CFS/ME, medical or behavioral. Behavioral
interventions are helpful for a number of major medical conditions (cardiovascular
disease, diabetes).
Illness “Reversal” and Behavioral Intervention
The most fundamental concern we have is focused on the type of causal model that was
linked to the CBT and GET conditions in this study. The model, based on the application
of cognitive-behavioral and physical conditioning principles, predicts that properly
designed behavioral or exercise interventions will “reverse” the CFS illness. Not improve
symptoms/functioning or provide better management, but “reverse” the illness. This term
implies that the illness can be cured (or something close to it) with behavioral
techniques.
If one assumes such a direct correspondence between behavioral treatment and curative
outcomes, then the illness is by implication a psychiatric condition. Once this
assumption is made, then research efforts to assemble a biomedical model of CFS are more
likely to be delegitimized. And the public’s perception of the illness as simply being
tired is again reinforced. Perhaps this is the most unfortunate aspect of the PACE trial:
The omission of any reference to the medical complexity of this illness.
Furthermore, when one compares the study goal of illness “reversal” to the reported
outcomes, the support for such reversal is modest at best: 30% of GET and CBT patients
achieved normative physical functioning-- but the 30% figure was in comparison to 15% who
achieved such normative function in the standard medical care control condition.
Thus a more accurate statement of this finding would be: An additional15% of patients in
the CBT and GET conditions achieved normal functioning in comparison to standard medical
care. The critical standard of clinical significance is that a therapy results in
restoration of normal function. But their own data do not support reversal outcomes above
and beyond standard medical care for the vast majority of their subjects in the CBT and
GET conditions.
Question of CFS/ME Diagnosis
In addition, the 15% advantage over standard care for patients in CBT and GET can be
further questioned given that at least 1/3 of all patients did not meet the strict
international criteria for CFS (Table 1 in study)—the diagnostic protocol most often used
in published studies. Strict criteria for CFS are linked to poor prognosis and conversely,
subjects who don’t meet strict criteria for CFS have better outcomes. So the PACE trial
folded in a significant number of subjects who do not have CFS according to standard
criteria. Again this dilutes the significance of their findings as it makes it more
difficult to generalize to the population of people who do have CFS.
To put behavioral approaches in context—they can be quite helpful, but they hardly meet
the standard of clinical significance that would elevate them to curative interventions.
If this had been made clear in the study, it would have provoked far less controversy and
debate.
Media Mis-reports
Finally, the media message from this study has often been: “Exercise is good; Rest is
bad.” Although the PACE trial authors did not issue such a statement, I think there is
some responsibility to explain to the media that this type of recommendation is simplistic
and potentially harmful for patients with CFS/ME. Activity and exercise recommendations
must be based on a thorough evaluation and a sensitive individualized approach, not the
broad brush that has become the take home message of this study.
Fred Friedberg, PhD
President
IACFS/ME
Lydia
Lydia E. Neilson, M.S.M. , Founder
Chief Executive Officer
NATIONAL ME/FM ACTION NETWORK
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Nepean, ON K2H 8V7 Canada
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Fax 613.829.8518
Email: mefmaction(a)ncf.ca
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CONFERENCE - OTTAWA, CANADA
SEPTEMBER 22 - 25, 2011
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