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PACE Trial Results

Posted by PeterKemp on 02 Aug 2012 at 13:45 GMT

The PACE Trial results (White et al. 2011) for ‘improved’ show that Graded Exercise Therapy (GET) had an effect for 16% and Cognitive Behaviour Therapy (CBT) for 14% over and above the control group. The results for ‘normal ranges’ show that GET had an effect for 13% and CBT for 15%. The results produce a ‘number needed to treat’ figure of 7 (Sharpe. 2011). When 7 patients are treated, one will improve due to treatment.

The PACE Trial Protocol (White et al 2007) states:
"GET will be based on the illness model of deconditioning and exercise intolerance".
"CBT will be based on the illness model of fear avoidance".

For 2 different theories and treatments to result in such similar outcomes is potentially problematic. Clinical Trials are designed to avoid such coincidences. However, this might not be a coincidence because the theories and therapies have some important similarities:
• Both theories believe that there is no pathophysiology (excepting ‘deconditioning’)
• Both believe that the patient is only using a small amount of their potential for activity
• Both rationalize symptoms and
• Both are ‘based on a graded exposure to activity’ (White et al. 2011)
Therefore the 2 theories and therapies are fundamentally the same which could explain their similar results.

The CBT arm was based on ‘fear avoidance’. Fear avoidance refers to anxiety about activities that the patient believes will be painful or cause them harm. This is theorised to be an obstacle to rehabilitation. Addressing fear avoidance is straightforward and similar to treating phobia with desensitization. ‘Systematic disconfirmation’ (Asmundson et al 2004) or ‘graded exposure’ (George and Zeppieri 2009) are established approaches. There is even evidence that including ‘fear avoidant’ participants in research could give better results for a therapy because these patients record greater improvements (George and Stryker. 2011).

Patients with ‘Severe M.E.’ were excluded from the PACE Trial. Therefore the testing was largely carried out on those representing the 75% of patients that do not have the severe form of the illnesses. Those who are still working or studying could be included. Participants who are parents may still be looking after children and many will be maintaining family/social relations, managing personal and household care and other activities. Evidence from patients shows that many strive to maintain as much of a normal a life as they possibly can. This does not sound like significant ‘fear avoidance’. The fact that the 640 participants willingly joined and remained throughout the PACE Trial, shows that ‘fear avoidance’ does not affect to them to a very significant degree. If it did, they would have stayed at home. Therefore participant’s fear avoidance should be moderate and treatable.

Deconditioning should also be straightforward to treat. Anyone that does more than they did on the previous day will, within a week or a month be well on their way to full fitness. With no physical illness or injury to prevent this (according to the theory), people with M.E. and CFS should soon be fully recovered from deconditioning.

The PACE Trial represented the culmination of many years of theorising and research efforts by the investigators to prove their theories about M.E. and CFS. It took 9 years and cost the taxpayer £5 million. The researchers produced specialized treatment manuals for therapists and patients. Therapy was closely supervised and participants were followed-up for a year. Participant retention, adherence and satisfaction were very high. This was an all-out effort for the researchers to prove their theories. Yet the results prove their theories are wrong.

85% of participants did not ‘improve’ or reach ‘normal ranges’ due to GET or CBT. This shows that the theories on which the treatments were based are wrong. If the researcher’s theories were correct, it would be reasonable to expect the recovery of the majority as a result of GET or CBT. It seems probable that if 85% of participants had ‘improved’ due to GET or CBT the researchers would claim that this unequivocally proved their theories. The opposite should also be true. 85% failure unequivocally disproves their theories.

The PACE Trial has shown emphatically that GET and CBT do not treat M.E. and CFS. Therefore it is reasonable to speculate that the 15% that responded to these treatments were misdiagnosed. Those participants may have had illnesses that included deconditioning and fear-avoidance ameliorable with the therapies.

People with M.E. and CFS should not be expected to make-do with treatments that have been shown to be ineffective for their illnesses. GET and CBT should not be recommended to patients with these illnesses. They are a waste of time and money.

These are important findings of the PACE Trial, yet this information has not been publicized; it has been ignored in favour of information that appears to serve the purposes of the researchers. The evidence of the PACE Trial strongly supports the opinions of those who believe that there is underlying pathophysiology in M.E. and CFS. This opinion rationally explains the failure of GET and CBT to treat M.E. and CFS.

Peter Kemp

Asmundson, Gordon J.G., Vlaeyen, Johan W.S., Crombez, Geert editors. 2004. Understanding and Treating Fear of Pain. Oxford University Press. New York.

George, S. Z, Zeppieri G. 2009. Physical therapy utilization of graded exposure for patients with low back pain. Journal of Orthopaedic Sports Physiotherapy. Jul;39(7).

George, Steven Z., Stryker, Sandra E. 2011. Fear-Avoidance Beliefs and Clinical Outcomes for Patients Seeking Outpatient Physical Therapy for Musculoskeletal Pain Conditions. Journal of Orthopaedic Sports and Physical Therapy. 2011;41(4).

Sharpe, Professor M. 2011. COMPARISON OF TREATMENTS FOR CHRONIC FATIGUE SYNDROME. Health Report. [Online transcript]. Available at: Accessed July 24th 2012.

White, Professor P. D., et al. 2007. Protocol for the PACE Trial. BMC Neurology. [Online]. Available at: http://www.biomedcentral.... Accessed Aug 1st 2012.

White, Professor P. D., et al. 2011. Comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): a randomised trial. The Lancet. 2011; 377: 823–36.

Competing interests declared: M.E. patient and advocate

RE: PACE Trial Results

ZigZag replied to PeterKemp on 03 Aug 2012 at 00:20 GMT

It should also be noted that CBT failed to meet the threshold for a clinical useful outcome (clinically useful difference from SMC) for physical disability, and was found to be 'moderately effective' only for fatigue.

In terms of the proportion of participants who achieved a clinically useful outcome (clinically useful difference from SMC), the results were as follows:

CBT physical function 13% (NNT = 1 in 8)
CBT fatigue 11% (NNT = 1 in 9)

GET physical function 12% (NNT = 8)
GET fatigue 15% (NNT = 7)

By contrast, 58% (physical function) and 65% (fatigue) of the SMC group achieved a clinically useful outcome.

No competing interests declared.