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The PACE trial had 4 groups, each with around 160 patients: the members of one group had sessions of specialist medical care about 5 times over the year: the other three groups saw had specialist medical care 3 or 4 times, but also had an additional 12 to 15 sessions of Graded Exercise Therapy (GET), or of Cognitive Behaviour Therapy (CBT), or of Adaptive Pacing Therapy (APT). Their progress was tracked in a variety of ways and was measured at the start, after 12 weeks (half-way through), after 24 weeks (at the end of the courses) and after 52 weeks.

First let us look at the way that GET is claimed to moderately improve the fatigue levels of patients. We will focus on their assessment of fatigue using the continuous/Likert Chalder scale, which runs from 0 points to 33 points, where 33 points represents utter exhaustion (in the true sense of the term - not just feeling very tired). Patients were assessed at the start of the trial, after 12, after 24 and after 52 weeks. A drop in score therefore represents a drop in fatigue - an improvement in health.

(The animation below has a commentary.)



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Both of these graphs are flattening out. In the case of the red SMC line, the effect is obvious: the maximum improvement occurs in the first 12 weeks.

The green line, representing the average extra benefit produced by the GET sessions, a smaller benefit than the SMC produced, is also flattening out. It fits a classic exponential decay pattern, with a maximum benefit of a 3.5 point improvement after many years. There are similar graphs for GET and CBT for each of the other assessments used - click on the tab or link to 3-Further Graphs to see them.

In most cases, the scores of the patients who only had Specialist Medical Care showed more than half of the overall improvement in the scores of the GET+SMC and of the CBT+SMC groups, and to use that combined score to reach targets gives a false impression of the effectiveness of GET and CBT. It is like setting the minimum height standard for entry into the police force at 5 feet 10 inches, then allowing candidates to stand on a box over three feet high. Interestingly the patient satisfaction with SMC (50%) was below the level of satisfaction with GET and CBT (82% or more), which suggests that patients overestimated the relative value of GET and CBT. This is an important consideration when you realise that the two main assessments, fatigue and physical function, were made through questionnaires.

 

The next animation looks at the consequences of the average improvement being so low, and of the baseline score of the group (282) being so close to the end value of the scale (33). In this situation, it is very similar to the situation of describing the average salary of adults in the UK mentioned in the previous section where a few high earners lift the average (the mean) to an unrepresentative value. We do not have access to the raw data, so the example here is an illustration of the situation rather than an actual example.


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As you can see, with such a small average improvement, the consequence of just 2 in 15 patients making a reasonable amount of progress with GET is that the remaining 13 must have made very little progress, or even deteriorated. If just one patient in 15 were to have returned to "healthy", then the remaining 14 would have had to made very little progress or deteriorated in order to keep down the average improvement.

This situation is similar for the other measures, and for CBT. For that reason the case for applying GET or CBT to all patients with ME/CFS is neither an efficient use of resources, nor an effective use of patients' time and efforts.

 


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