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/fulltext)
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