Sharpe – American ME and CFS Society

Bias in Exercise Trials for ME/CFS: the Importance of Objective Outcomes and Long-term Follow-up

Sharpe and colleagues recommend that patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) be offered cognitive behavior therapy (CBT) and graded exercise therapy (GET)¹, advice that contrasts with recent NICE guidance on ME/CFS.² The authors argue that “there are many randomized trials indicating the safety and efficacy of these treatments.”¹

All of these trials, however, were nonblinded and relied on subjective symptom questionnaires as their main outcomes, a combination that creates a high risk of response bias. Treatment manuals used in these trials included explicit encouragements to raise patients’ expectations of GET and CBT. One patient booklet, for example, informed patients: “You will experience a snowballing effect as increasing fitness leads to increasing confidence in your ability. You will have conquered CFS by your own effort and you will be back in control of your body again.”³ These encouragements were not provided to participants in the control group and might have influenced how patients rated their health. In contrast to what Sharpe and colleagues claim, measuring the expectations of patients before the trial begins, does not address how therapists might have influenced symptom reporting during the trial.

There are further arguments that suggest these trials might have measured response bias rather than improvements in health. There were, for example, no clinically significant differences on objective outcome measures that are less prone to response bias such as employment figures, activity levels, or fitness tests.³ In addition, at long-term follow-up, the control group seemed to perform just as well as participants who received GET or CBT. This could not be explained by additional treatment received after the trial ended.⁴ These findings are difficult to interpret if patients did indeed rehabilitate successfully following GET or CBT. It is unfortunate that the authors, who were primary researchers in many of these trials, do not address these concerns.

Lastly, Sharpe and colleagues argue that “harm reported from patient community surveys reflects poorly implemented therapy.”¹ Patient surveys, however, indicate that ME/CFS patients report harm of GET even if prescribed by a specialist or physiotherapist.⁵ The authors have previously been challenged for misrepresenting the findings of these surveys.⁵ Post-exertional malaise or a marked worsening of symptoms when patients exceed their energy limit, is a characteristic feature of ME/CFS.² There are therefore reasonable safety concerns about treatments such as GET and CBT that try to push patients to exceed their limits.

Read the full article HERE.

Source: Tack, M. Bias in Exercise Trials for ME/CFS: the Importance of Objective Outcomes and Long-term Follow-up. J GEN INTERN MED 37, 3193 (2022). https://doi.org/10.1007/s11606-022-07704-0 (Full text)

Patterns of Daytime Physical Activity in Patients With Chronic Fatigue Syndrome

Abstract:

Objectives: To classify patients with chronic fatigue syndrome (CFS) by pattern of physical activity and determine the clinical associations of each type.

Methods: 579 out of 641 participants with CFS from the PACE (Pacing, graded Activity, Cognitive behavioural therapy: a randomised Evaluation) trial wore an Actiwatch (accelerometer) for between 3 and 7 days before any trial treatments, which provided a measure of physical activity. Participants’ activity was categorised into one of four patterns (pervasively inactive, pervasively active, boom and bust, or indeterminate) primarily using a priori definitions of activity. Clinical associations were sought with each group using an exploratory logistic regression with the indeterminate activity group being the reference group.

Results: 124 (21%) of the participants were classified as pervasively inactive, 65 (11%) as pervasively active, 172 (30%) showed a ‘boom and bust’ pattern of activity, and 218 (38%) had an indeterminate pattern. Pervasively inactive patients were more physically disabled, those in the pervasively active group were more anxious, and those in the boom and bust group had more sleep disturbance.

Conclusion: We were able to classify patients with CFS into groups by their daytime activity pattern. The different patterns of activity were associated with important clinical variables, suggesting that they might be helpful in determining prognosis and targeting treatments. These associations need replication.

Conceptualising illness and disease: reflections on Sharpe and Greco (2019)

Abstract:

In a recent paper, Sharpe and Greco suggest that chronic fatigue syndrome/myalgic encephalomyelitis (MECFS) can be viewed as an instance of “illness without disease”, and consequently, treatment should be directed towards altering the patient’s experience of, and response to, their symptoms. We discuss two broad issues that arise from Sharpe and Greco’s article, one relating to the assumptions they make about MECFS and its treatment specifically, and the other relating to their conceptualisation of the illness/disease dichotomy.

We argue that the term “illness without disease”, in the sense that Sharpe and Greco use it, is problematic because it can lead to unwarranted causal assumptions. Following these critical comments, we present a new framework for conceptualising the relationship between explanatory disease models and the experience of illness.

Source: Wilshire C, Ward T. Conceptualising illness and disease: reflections on Sharpe and Greco (2019). Med Humanit. 2019 Dec 11. pii: medhum-2019-011756. doi: 10.1136/medhum-2019-011756. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31826926 (Abstract) https://sci-hub.se/10.1136/medhum-2019-011756 (Full article)

Chronic fatigue syndrome and an illness-focused approach to care: controversy, morality and paradox

Abstract:

Contemporary medicine distinguishes between illness and disease. Illness refers to a person’s subjective experience of symptoms; disease refers to objective bodily pathology. For many illnesses, medicine has made great progress in finding and treating associated disease. However, not all illnesses are successfully relieved by treating the disease. In some such cases, the patient’s suffering can only be reduced by treatment that is focused on the illness itself. Chronic disabling fatigue is a common symptom of illness, for which disease-focused treatment is often not effective, but for which illness-focused treatments (psychological or behavioural) often are.

In this article, we explore a controversy surrounding illness-focused treatments for fatigue. We do this by contrasting their acceptance by people whose fatigue is associated with a disease (using the example of cancer-related fatigue) with their controversial rejection by some people whose fatigue is not associated with an established disease (chronic fatigue syndrome or CFS, sometimes called ME (myalgic encephalomyelitis)). In order to understand this difference in acceptability we consider the differing moral connotations of illness and disease and then go on to examine the limitations of the concepts of illness and disease themselves.

We conclude that a general acceptance of illness-focused treatments by all who might benefit from them will require a major long-term change in thinking about illness, but that improvements to the care of individual patients can be made today.

Source: Sharpe M, Greco M. Chronic fatigue syndrome and an illness-focused approach to care: controversy, morality and paradox. Med Humanit. 2019 Jun 18. pii: medhum-2018-011598. doi: 10.1136/medhum-2018-011598. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31213482

Response to the editorial by Dr Geraghty

Abstract:

This article is written in response to the linked editorial by Dr Geraghty about the adaptive Pacing, graded Activity and Cognitive behaviour therapy; a randomised Evaluation (PACE) trial, which we led, implemented and published. The PACE trial compared four treatments for people diagnosed with chronic fatigue syndrome. All participants in the trial received specialist medical care. The trial found that adding cognitive behaviour therapy or graded exercise therapy to specialist medical care was as safe as, and more effective than, adding adaptive pacing therapy or specialist medical care alone. Dr Geraghty has challenged these findings. In this article, we suggest that Dr Geraghty’s views are based on misunderstandings and misrepresentations of the PACE trial; these are corrected.

Source: White PD, Chalder T, Sharpe M, Angus BJ, Baber HL, Bavinton J, Burgess M, Clark LV, Cox DL, DeCesare JC, Goldsmith KA, Johnson AL, McCrone P, Murphy G, Murphy M, O’Dowd H, Potts L, Walwyn R, Wilks D. Response to the editorial by Dr Geraghty. J Health Psychol. 2017 Aug;22(9):1113-1117. doi: 10.1177/1359105316688953. Epub 2017 Jan 24. https://www.ncbi.nlm.nih.gov/pubmed/28805524

Long-term economic evaluation of cognitive-behavioural group treatment versus enhanced usual care for functional somatic syndromes

Abstract:

OBJECTIVE: Patients with functional somatic syndromes (FSS) such as fibromyalgia and chronic fatigue syndrome have a poor outcome and can incur high healthcare and societal costs. We aimed to compare the medium-term (16 months) cost-effectiveness and the long-term (40 months) economic outcomes of a bespoke cognitive-behavioural group treatment (STreSS) with that of enhanced usual care (EUC).

METHODS: We obtained complete data on healthcare and indirect costs (i.e. labour marked-related and health-related benefits) from public registries for 120 participants from a randomised controlled trial. Costs were calculated as per capita public expenses in 2010 €. QALYs gained were estimated from the SF-6D. We conducted a medium-term cost-effectiveness analysis and a long-term cost-minimization analysis from both a healthcare (i.e. direct cost) and a societal (i.e. total cost) perspective.

RESULTS: In the medium term, the probability that STreSS was cost-effective at thresholds of 25,000 to 35,000 € per QALY was 93-95% from a healthcare perspective, but only 50-55% from a societal perspective. In the long term, however, STreSS was associated with increasing savings in indirect costs, mainly due to a greater number of patients self-supporting. When combined with stable long-term reductions in healthcare expenditures, there were total cost savings of 7184 € (95% CI 2271 to 12,096, p=0.004) during the third year after treatment.

CONCLUSION: STreSS treatment costs an average of 1545 €. This cost was more than offset by subsequent savings in direct and indirect costs. Implementation could both improve patient outcomes and reduce costs.

Source: Schröder A, Ørnbøl E, Jensen JS, Sharpe M, Fink P. Long-term economic evaluation of cognitive-behavioural group treatment versus enhanced usual care for functional somatic syndromes. J Psychosom Res. 2017 Mar;94:73-81. doi: 10.1016/j.jpsychores.2017.01.005. Epub 2017 Jan 10. https://www.ncbi.nlm.nih.gov/pubmed/28183406

Rehabilitative therapies for chronic fatigue syndrome: a secondary mediation analysis of the PACE trial

Abstract:

BACKGROUND: Cognitive behaviour therapy (CBT) added to specialist medical care (SMC), or graded exercise therapy (GET) added to SMC, are more effective in reducing fatigue and improving physical function than both adaptive pacing therapy (APT) plus SMC and SMC alone for chronic fatigue syndrome. We investigate putative treatment mechanisms.

METHODS: We did a planned secondary mediation analysis of the PACE trial comparing SMC alone or SMC plus APT with SMC plus CBT and SMC plus GET for patients with chronic fatigue syndrome. 641 participants were recruited from six specialist chronic fatigue syndrome clinics in the UK National Health Service between March 18, 2005, and Nov 28, 2008. We assessed mediation using the product of coefficients method with the 12 week measure of the mediators and the 52 week measure of the outcomes. The primary outcomes were fatigue measured by the Chalder fatigue scale and physical function measured by the physical function subscale of the SF-36. We included confounder covariates and used treatment by mediator interaction terms to examine differences in mediator-outcome relations by treatment group.

FINDINGS: The largest mediated effect for both CBT and GET and both primary outcomes was through fear avoidance beliefs with an effect of larger magnitude for GET (standardised effects ×10, CBT vs APT, fatigue -1.22, 95% CI -0.52 to -1.97, physical function 1.54, 0.86 to 2.31; GET vs APT, fatigue -1.86, -0.80 to -2.89, physical function 2.35, 1.35 to 3.39). Increase in exercise tolerance (6 min walk distance) was a potent mediator of the effect of GET (vs APT, fatigue -1.37, 95% CI -0.76 to -2.21, physical function 1.90, 1.10 to 2.91), but not CBT.

INTERPRETATION: Our main finding was that fear avoidance beliefs were the strongest mediator for both CBT and GET. Changes in both beliefs and behaviour mediated the effects of both CBT and GET, but more so for GET. The results support a treatment model in which both beliefs and behaviour play a part in perpetuating fatigue and disability in chronic fatigue syndrome.

FUNDING: UK Medical Research Council, Department of Health for England, Scottish Chief Scientist Office, Department for Work and Pensions, National Institute for Health Research (NIHR), NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust, and Institute of Psychiatry, Psychology, and Neuroscience, King’s College London.

Source: Chalder T, Goldsmith KA, White PD, Sharpe M, Pickles AR. Rehabilitative therapies for chronic fatigue syndrome: a secondary mediation analysis of the PACE trial. Lancet Psychiatry. 2015 Feb;2(2):141-52. doi: 10.1016/S2215-0366(14)00069-8. Epub 2015 Jan 28. https://www.ncbi.nlm.nih.gov/pubmed/26359750

Comment in

Omission of data weakens the case for causal mediation in the PACE Trial. [Lancet Psychiatry. 2015]
In non-blinded trials, self-report measures could mislead. [Lancet Psychiatry. 2015]
What makes a difference in chronic fatigue syndrome? [Lancet Psychiatry. 2015]
Doubts over the validity of the PACE hypothesis. [Lancet Psychiatry. 2015]
Methods and outcome reporting in the PACE trial–Author’s reply. [Lancet Psychiatry. 2015]
Methods and outcome reporting in the PACE trial. [Lancet Psychiatry. 2015]
Post-exertional malaise in chronic fatigue syndrome. [Lancet Psychiatry. 2015]

COMMENTS

Robert Courtney 2016 Feb 16 10:20 a.m
A study that uses questionable assumptions rather than empirical evidence leads to conclusions that stretch credibility.

Chalder et al. [1] used the “single mediation model” for their methodology, which is explained in detail in a book by MacKinnon [2]. Explaining the methodology MacKinnon says a temporal separation between variables must be observed (i.e. changes in mediating variable must occur before changes in the mediated variable) for a mediation effect to be empirically and robustly established.

Chalder et al. were working to this model and acknowledged that they failed to establish a clear temporal separation between variables, and therefore did not empirically establish a causal mediation effect: “Given the pattern of change in the mediators was similar to the pattern of change in the outcomes it is possible that the variables were affecting each other reciprocally”.

However, despite the lack of robust empirical evidence to support a mediation effect, the investigators concluded that they had established mediation effects, e.g: “Our main finding was that fear avoidance beliefs were the strongest mediator for both CBT and GET.”

The study’s conclusion relied upon an assumption that the investigators’ favoured hypothetical model of illness for ME/CFS has a robust empirical evidence base and is applicable to this study. The hypothesis is based upon the idea that symptoms and disability in ME/CFS are perpetuated by unhelpful or maladaptive illness beliefs, fear, and an avoidance of activity.

However, the prestigious National Academy of Medicine (formerly known as the Institute of Medicine) recently released a comprehensive report [3] into ME/CFS that rejected such a hypothetical model of illness, and unambiguously concluded that ME/CFS does not have a psychological or cognitive-behavioural basis, but is an organic illness that requires biomedical research.

Chalder et al. discussed the possibility that more frequent measurements may have potentially demonstrated a temporal separation between the variables, and therefore a mediation effect. However, this raises the possibility of whether changes in the primary outcome variables (self-report physical function and fatigue) may, in fact, have occurred before changes in the presumed mediator variables. Such an outcome would entirely contradict the investigators’ premature conclusions. According to MacKinnon [2] and Wiedermann et al. [4], unexpected outcomes should not be ruled out.

Chalder et al. concluded that symptoms and physical impairment, in ME/CFS patients, are mediated by activity avoidance and other factors. (e.g. This would mean that a decrease in activity would cause an increase in symptoms.) However, from a common sense point of view, this seems like rather a convoluted conclusion, and it seems more likely that increased symptoms would be the direct cause of activity avoidance in any illness, rather than vice versa. To conclude that activity avoidance causes fatigue (rather than fatigue being a direct cause of activity avoidance), is similar to concluding that a person has flu because they’ve taken a day off work, rather than the obvious conclusion that they’ve taken a day off work because they have flu.

In the case of fatigue, flu-like malaise and other symptoms of ME/CFS, it seems reasonable to consider the possibility that, as the symptoms fluctuate, patients may intuitively or rationally adapt their activity levels according to what is comfortable and safe. i.e. patients reduce activity levels because they are fatigued. The investigators have concluded that patients are fatigued because they have reduced activity levels.

Perhaps patients’ perspectives and insights would help clarify the issues but, unfortunately, patients were not consulted for this study.

References:
1. Chalder T, Goldsmith KA, White PD, Sharpe M, Pickles AR. Rehabilitative therapies for chronic fatigue syndrome: a secondary mediation analysis of the PACE trial. Lancet Psychiatry 2015; 2: 141–52.
2. MacKinnon DP. Introduction to Statistical Mediation Analysis. Taylor and Francis: New York 2008.
3. IOM (Institute of Medicine). 2015. Beyond myalgic encephalomyelitis/chronic fatigue syndrome: Redefining an illness. Washington, DC: The National Academies Press. http://iom.nationalacademies.org/Reports/2015/ME-CFS.aspx
4. Wiedermann W, von Eye A. Direction of Effects in Mediation Analysis. Psychol Methods 2015; 20: 221-44.
Permalink Share

Tom Kindlon 2015 Sep 15 09:53 a.m.

Objective measures found a lack of improvement for CBT & GET in the PACE Trial: subjective improvements may simply represent response biases or placebo effects in this non-blinded trial

[Originally posted here: http://www.bmj.com/content/350/bmj.h227/rr-10]

This BMJ article and a flurry of articles in the lay media this week followed the publication in Lancet Psychiatry of an analysis of the mediators of change in the important PACE Trial, a chronic fatigue syndrome (CFS) trial which cost UK taxpayers £5 million[1,2]. What seems to have been lost in the coverage is that, although there were some modest improvements in the self-report measures, there was an almost complete absence of improvements in objectively measured outcomes for cognitive behavioural therapy (CBT) and graded exercise therapy (GET) compared to the control group (specialist medical care only (SMC)).

This is a non-blinded trial, where participants were told CBT and GET had previously been found to be effective in CFS and other conditions[3,4]: one way to look at the mediation results for subjective measures when there was a lack of objective improvements is that they may merely tell us how response biases and/or placebo effects are mediated[5].

The focus on subjective measures in some CFS studies was previously criticised in a systematic review published back in 2001 (long before the PACE Trial started)[6]. They suggested instead “a more objective measure of the effect of any intervention would be whether participants have increased their working hours, returned to work or school, or increased their physical activities.”

The model presented for cognitive behaviour therapy (CBT) in the PACE Trial manuals posits that the impairments and symptoms are reversible with the therapy[3,7]. However, the latest paper shows that fitness, as measured by a step test, didn’t improve following CBT[2]. An earlier PACE Trial publication reported that the addition of CBT to SMC did not result in an improvement in 6-minute walking test scores compared to SMC alone[8].

The PACE Trial was part funded by the UK Department of Work and Pensions, a rare move for them, presumably done due to an expectation that the therapies would improve measures of employment and levels of benefit receipt. However, again CBT brought about no improvement using objective measures, such as days of employment lost, levels of disability benefits received and levels of receipt of insurance payments[9].

These results are in line with earlier studies of CBT. For example, an analysis of three randomized controlled trials of CBT interventions for CFS found no improvement in objectively measured activity, despite participants reporting a reduction in (self-reported) fatigue and (sometimes) functional impairments[10]. Similar results were found in another uncontrolled trial where changes in objectively measured activity did not predict fatigue levels, and objectively measured activity on completion remained low compared to population norms[11]. An uncontrolled study found improvements in self-reported physical functioning and fatigue were reported despite a numerical decrease in (objectively measured) activity[12]. In another study, the level of self-reported cognitive impairment in CFS patients decreased significantly after CBT, however, cognition had not improved when it was measured objectively using neuropsychological test performance[13].

It is unsurprising that 15 sessions of CBT (and the associated homework exercises and management program) might alter how participants respond to self-report questionnaires. A PACE Trial manual itself says “the essence of CBT is helping the participant to change their interpretation of symptoms”: this could lead to altered or biased fatigue scores, one of the two primary outcome measures[14]. Also, one of the aims of CBT (for CFS) has been said to be “increased confidence in exercise and physical activity”[15]. The possible responses for the other primary outcome measure, the SF-36 physical functioning subscale, are “yes, limited a lot”, “yes, limited a little” and “no, not limited at all” to questions on a range of physical activities. Such responses could be easily be artificially altered following a therapy like CBT for CFS.

The results were not that different with the GET cohort in the PACE Trial. Again the manuals predicted that the impairments and symptoms are reversible using the intervention[4,15]. The model said there was no reason participants should not be able to get back to full functioning. Deconditioning was posited to be an important maintaining factor. However, GET did not result in an improvement in fitness, as measured by the step test. GET did result in a small improvement on the six minute walking test to a final distance of 379 metres, or 35 metres more than the SMC-only group[7]. However, as Knoop and Wiborg commented in an accompanying editorial in Lancet Psychiatry: “an increase in distance walked during a test situation without an increased fitness suggests that patients walk more because of a change in cognitive processes (eg, daring to do more or an increased self-efficacy with respect to activity), not because of a change in physiological capacity”[16]. The result remained very poor given that normative data would suggest a group of similar age and gender should walk an average of 644 or so metres[17]. The distance walked remained comparable to people with many serious conditions[18-21], and considerably worse than the distance walked by healthy elderly adults[22,23], despite the PACE trial cohort having a mean age of only 40[8]. Also, to be allowed entry into CFS research studies such as the PACE Trial one can not have a range of chronic illnesses so with genuine recovery one would expect results comparable to healthy people[8].

As with CBT, measures relating to employment showed no improvement following GET in days of work missed, which remained very high, nor a reduction in levels of benefits (financial support from the state) or payments from insurance companies[9].

These results are in line with an audit of Belgian rehabilitation centres for CFS offering CBT and GET[24-26]. Some improvements in subjective measures were found, but there was no improvement in the results of the exercise test and hours in employment actually decreased.

Probably the main contribution of the PACE Trial has been to add to a growing body of evidence that while CBT and GET for CFS have resulted in some changes on subjective measures, they haven’t lead to improvements on objective measures.

Competing interests: I am a committee member of the Irish ME/CFS Association and perform various types of voluntary work for the Association.

(continues)

Permalink Share
- Tom Kindlon 2015 Sep 15 09:55 a.m.
  
  (Contd.)
  
  References:
  
  1 Torjesen I. Tackling fears about exercise is important for ME treatment, analysis indicates. BMJ 2015;350:h227 http://www.bmj.com/content/350/bmj.h227
  
  2 Chalder T, Goldsmith KA, White PD, Sharpe M, Pickles AR. Rehabilitative therapies for chronic fatigue syndrome: a secondary mediation analysis of the PACE trial. Lancet Psychiatry 14 Jan 2015, doi:10.1016/S2215-0366(14)00069-8.
  
  3 Burgess M, Chalder T. Manual for Participants. Cognitive behaviour therapy for CFS/ME.http://www.pacetrial.org/docs/cbt-participant-manual.pdf (accessed: January 17, 2015)
  
  4 Bavinton J, Darbishire L, White PD -on behalf of the PACE trial management group. Graded Exercise Therapy for CFS/ME. Information for Participants http://www.pacetrial.org/docs/get-participant-manual.pdf (accessed: January 17, 2015)
  
  5 Wechsler ME, Kelley JM, Boyd IO, Dutile S, Marigowda G, Kirsch I, Israel E, Kaptchuk TJ. Active albuterol or placebo, sham acupuncture, or no intervention in asthma. N Engl J Med. 2011;365(2):119-26.
  
  6 Whiting P, Bagnall AM, Sowden AJ, Cornell JE, Mulrow CD, Ramírez G. Interventions for the treatment and management of chronic fatigue syndrome: a systematic review. JAMA. 2001 Sep 19;286(11):1360-8.
  
  7 Burgess M, Chalder T. PACE manual for therapists. Cognitive behaviour therapy for CFS/ME.http://www.pacetrial.org/docs/cbt-therapist-manual.pdf (accessed: January 17, 2015)
  
  8 White PD, Goldsmith KA, Johnson AL, Potts L, Walwyn R, DeCesare JC, et al, for the PACE trial management group. Comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): a randomised trial. Lancet 2011;377:823-36.
  
  9 McCrone P, Sharpe M, Chalder T, Knapp M, Johnson AL, Goldsmith KA, White PD. Adaptive pacing, cognitive behaviour therapy, graded exercise, and specialist medical care for chronic fatigue syndrome: a cost-effectiveness analysis. PLoS One. 2012;7(8):e40808. doi: 10.1371/journal.pone.0040808
  
  10 Wiborg JF, Knoop H, Stulemeijer M, Prins JB, Bleijenberg G. How does cognitive behaviour therapy reduce fatigue in patients with chronic fatigue syndrome? The role of physical activity. Psychol Med. 2010 Aug;40(8):1281-7. doi: 10.1017/S0033291709992212. Epub 2010 Jan 5.
  
  11 Heins MJ, Knoop H, Burk WJ, Bleijenberg G. The process of cognitive behaviour therapy for chronic fatigue syndrome: which changes in perpetuating cognitions and behaviour are related to a reduction in fatigue? J Psychosom Res. 2013 Sep;75(3):235-41. doi: 10.1016/j.jpsychores.2013.06.034. Epub 2013 Jul 19.
  
  12 Friedberg F, Sohl S. Cognitive-behavior therapy in chronic fatigue syndrome: is improvement related to increased physical activity? J Clin Psychol. 2009 Apr;65(4):423-42. doi: 10.1002/jclp.20551.
  
  13 Knoop H, Prins JB, Stulemeijer M, van der Meer JW, Bleijenberg G. The effect of cognitive behaviour therapy for chronic fatigue syndrome on self-reported cognitive impairments and neuropsychological test performance. Journal of Neurology and Neurosurgery Psychiatry. 2007 Apr;78(4):434-6.
  
  14 Bavinton J, Darbishire L, White PD -on behalf of the PACE trial management group. Graded Exercise Therapy for CFS/ME (Therapist manual): http://www.pacetrial.org/docs/get-therapist-manual.pdf (accessed: January 17, 2015)
  
  15 O’Dowd H, Gladwell P, Rogers CA, Hollinghurst S, Gregory A. Cognitive behavioural therapy in chronic fatigue syndrome: a randomised controlled trial of an outpatient group programme. Health Technology Assessment, 2006, 10, 37, 1-140.
  
  16 Knoop H, Wiborg JF. What makes a difference in chronic fatigue syndrome? Lancet Psychiatry 13 Jan 2015 DOI: http://dx.doi.org/10.1016/S2215-0366(14)00145-X
  
  17 Kindlon T. Reporting of Harms Associated with Graded Exercise Therapy and Cognitive Behavioural Therapy in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Bulletin of the IACFS/ME. 2011;19(2):59-111http://iacfsme.org/BULLETINFALL2011/Fall2011KindlonHarmsPaperABSTRACT/ta…
  
  18 Lipkin DP, Scriven AJ, Crake T, Poole-Wilson PA. Six minute walking test for assessing exercise capacity in chronic heart failure. Br Med J (Clin Res Ed) 1986. 292:653–655.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1339640/pdf/bmjcred00224-001…
  
  19 Marin JM, Carrizo SJ, Gascon M, Sanchez A, Gallego B, Celli BR. Inspiratory Capacity, Dynamic Hyperinflation, Breathlessness, and Exercise Performance during the 6-Minute-Walk Test in Chronic Obstructive Pulmonary Disease. Am. J. Respir. Crit. Care Med. 2001 63(6):1395-1399.http://171.66.122.149/content/163/6/1395.full
  
  20 Goldman MD, Marrie RA, Cohen JA. Evaluation of the six-minute walk in multiple sclerosis subjects and healthy controls. Multiple Sclerosis 2008. 14(3):383-390.http://pocketknowledge.tc.columbia.edu/home.php/viewfile/download/65399/The six-minute walk test.pdf
  
  21 Ross RM, Murthy JN, Wollak ID, Jackson AS. The six minute walk test accurately estimates mean peak oxygen uptake. BMC Pulm Med. 2010 May 26;10:31. PMID 20504351.http://www.biomedcentral.com/1471-2466/10/31
  
  22 Camarri B, Eastwood PR, Cecins NM, Thompson PJ, Jenkins S. Six minute walk distance in healthy subjects aged 55–75 years. Respir Med. 2006. 100:658-65 http://www.resmedjournal.com/article/S0954-6111(05)00326-4/abstract
  
  23 Troosters T, Gosselink R, Decramer M. Six minute walking distance in healthy elderly subjects. Eur Respir J. 1999. 14:270-4. http://www.ersj.org.uk/content/14/2/270.full.pdf
  
  24 Rapport d’évaluation (2002-2004) portant sur l’exécution des conventions de rééducation entre le Comité de l’assurance soins de santé (institué auprès de l’Institut national d’assurance maladie invalidité) et les Centres de référence pour le Syndrome de fatigue chronique (SFC), Bruxelles, juillet 2006. (French language edition)
  
  25 Evaluatierapport (2002-2004) met betrekking tot de uitvoering van de revalidatieovereenkomsten tussen het Comité van de verzekering voor geneeskundige verzorging (ingesteld bij het Rijksinstituut voor Ziekte- en invaliditeitsverzekering) en de Referentiecentra voor het Chronisch vermoeidheidssyndroom (CVS). 2006. Available online:https://drive.google.com/file/d/0BxnVj9ZqRgk0QTVsU2NNLWJSblU/edit (accessed: January 17, 2015) (Dutch language version)
  
  26 Stordeur S, Thiry N, Eyssen M. Chronisch Vermoeidheidssyndroom: diagnose, behandeling en zorgorganisatie. Health Services Research (HSR). Brussel: Federaal Kenniscentrum voor de Gezondheidszorg (KCE); 2008. KCE reports 88A (D/2008/10.273/58)https://kce.fgov.be/sites/default/files/page_documents/d20081027358.pdf (accessed: January 17, 2015)

The planning, implementation and publication of a complex intervention trial for chronic fatigue syndrome: the PACE trial

Abstract:

The PACE trial was a four-arm trial of specialist medical care, compared with specialist medical care with a supplementary therapy: adaptive pacing therapy, cognitive-behavioural therapy or graded exercise therapy, for patients with chronic fatigue syndrome. The trial found that both cognitive-behavioural and graded exercise therapies were more effective than either of the other two treatments in reducing fatigue and improving physical disability. This paper describes the design, conduct and main results of the trial, along with a description of the challenges that had to be overcome in order to produce clear answers to the clinically important questions the trial posed.

Source: White PD, Chalder T, Sharpe M. The planning, implementation and publication of a complex intervention trial for chronic fatigue syndrome: the PACE trial. BJPsych Bull. 2015 Feb;39(1):24-7. doi: 10.1192/pb.bp.113.045005. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4495840/ (Full article)

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

Abstract:

OBJECTIVE: 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.

METHODS: 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.

RESULTS: 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=.47). A greater number of NSAEs were associated with recruitment centre, and baseline physical symptom count, body mass index, and depressive disorder. Physical function deteriorated in 39 (25%) participants after APT, 15 (9%) after CBT, 18 (11%) after GET, and 28 (18%) after SMC (P<.001), with no significant differences in worsening fatigue.

CONCLUSIONS: The 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.

Source: Dougall D, Johnson A, Goldsmith K, Sharpe M, Angus B, Chalder T, White P. Adverse events and deterioration reported by participants in the PACE trial of therapies for chronic fatigue syndrome. J Psychosom Res. 2014 Jul;77(1):20-6. doi: 10.1016/j.jpsychores.2014.04.002. Epub 2014 Apr 22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4065570/ (Full article)

Comment:

Tom Kindlon 2016 Jan 08 3:56 p.m.

“Trial By Error, Continued: Did the PACE Trial Really Prove that Graded Exercise Is Safe?”

By two science journalists: (i) Julie Rehmeyer is a journalist and Ted Scripps Environmental Journalism Fellow at the University of Colorado, Boulder, who has written extensively about ME/CFS and (ii) David Tuller DrPH is academic coordinator of the concurrent masters degree program in public health and journalism at the University of California, Berkeley.

I am quoted in it.

http://www.virology.ws/2016/01/07/trial-by-error-continued-did-the-pace-trial-really-prove-that-graded-exercise-is-safe/

A randomised trial of adaptive pacing therapy, cognitive behaviour therapy, graded exercise, and specialist medical care for chronic fatigue syndrome (PACE): statistical analysis plan.

Abstract:

BACKGROUND: The publication of protocols by medical journals is increasingly becoming an accepted means for promoting good quality research and maximising transparency. Recently, Finfer and Bellomo have suggested the publication of statistical analysis plans (SAPs).The aim of this paper is to make public and to report in detail the planned analyses that were approved by the Trial Steering Committee in May 2010 for the principal papers of the PACE (Pacing, graded Activity, and Cognitive behaviour therapy: a randomised Evaluation) trial, a treatment trial for chronic fatigue syndrome. It illustrates planned analyses of a complex intervention trial that allows for the impact of clustering by care providers, where multiple care-providers are present for each patient in some but not all arms of the trial.

RESULTS: The trial design, objectives and data collection are reported. Considerations relating to blinding, samples, adherence to the protocol, stratification, centre and other clustering effects, missing data, multiplicity and compliance are described. Descriptive, interim and final analyses of the primary and secondary outcomes are then outlined.

CONCLUSIONS: This SAP maximises transparency, providing a record of all planned analyses, and it may be a resource for those who are developing SAPs, acting as an illustrative example for teaching and methodological research. It is not the sum of the statistical analysis sections of the principal papers, being completed well before individual papers were drafted.

TRIAL REGISTRATION: ISRCTN54285094 assigned 22 May 2003; First participant was randomised on 18 March 2005.

Source: Walwyn R, Potts L, McCrone P, Johnson AL, DeCesare JC, Baber H, Goldsmith K, Sharpe M, Chalder T, White PD. A randomised trial of adaptive pacing therapy, cognitive behaviour therapy, graded exercise, and specialist medical care for chronic fatigue syndrome (PACE): statistical analysis plan. Trials. 2013 Nov 13;14:386. doi: 10.1186/1745-6215-14-386. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4226009/ (Full article)