PACE Trial: report on adverse events involved in therapies used in the trial | Journal of Psychosomatic Research | 22 April 2014

April 26, 2014

From the Journal of Psychosomatic Research, available online 22 April 2014.

Adverse events and deterioration reported by participants in the PACE trial of therapies for chronic fatigue syndrome

Dominic Dougall (a), A.L. Johnson (b), K. Goldsmith ©, M. Sharpe (d), B. Angus (e), T. Chalder (f), P.D. White (g), Corresponding author
a) East London Foundation NHS Trust, London
b) MRC Clinical Trials Unit at UCL, London
c) Biostatistics Department, Institute of Psychiatry, King’s College London
d) Psychological Medicine Research, Department of Psychiatry, University of Oxford, Oxford, UK
e) Nuffield Department of Medicine, University of Oxford
f) Academic Department of Psychological Medicine, King's College London
g) Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London


• This study shows the distribution of adverse events in a trial of treatments for CFS.

• Non-serious adverse events were common, but no different between treatments.

• Non-serious adverse events were more related to ill health than treatments.

• Deterioration in physical function was more likely after adaptive pacing therapy.

• Differences between centres may be related to different ascertainment methods.



Adverse events (AEs) are health related events, reported by participants in clinical trials. We describe AEs in the PACE trial of treatments for chronic fatigue syndrome (CFS) and baseline characteristics associated with them.


AEs were recorded on three occasions over one year in 641 participants.

We compared the numbers and nature of AEs between treatment arms of specialist medical care (SMC) alone, or SMC supplemented by adaptive pacing therapy (APT), cognitive behaviour therapy (CBT) or graded exercise therapy (GET).

We examined associations with baseline measures by binary logistic regression analyses, and compared the proportions of participants who deteriorated by clinically important amounts.


Serious adverse events and reactions were infrequent.

Non-serious adverse events were common; the median (quartiles) number was 4 (2, 8) per participant, with no significant differences between treatments (p = 0.47).

A greater number of NSAEs was associated with recruitment centre, and baseline physical symptom count, body mass index, and depressive disorder.

Physical function deteriorated in 39 (25%) of participants after APT, 15 (9%) after CBT, 18 (11%) after GET, and 28 (18%) after SMC (p < 0.001), with no significant differences in worsening fatigue.CONCLUSIONSThe numbers of adverse events did not differ significantly between trial treatments, but physical deterioration occurred most often after APT.The reporting of non-serious adverse events may reflect the nature of the illness rather than the effect of treatments.Differences between centres suggest that both standardisation of ascertainment methods and training are important when collecting adverse event data.

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