PACE trial

The PACE Trial (short for "Pacing, graded Activity, and Cognitive behaviour therapy; a randomised Evaluation") was a large-scale trial to compare the effectiveness of four treatments for people suffering from chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME).

The study compared standardised specialist medical care (SMC) alone to SMC plus adaptive pacing therapy (APT), cognitive behavioral therapy (CBT), or Graded Exercise Therapy (GET). The experimenters hypothesised that the CBT and GET groups would do best, and claimed that this is what the trial's results showed: but the trial design, the extensive changes to planned analyses and the conclusions drawn from the results by PACE's authors have been heavily criticized by patients and scientists alike.

The 2015 follow-up study showed no significant benefits from these treatments after 2.5 years.

Despite the raging controversy, and ineffectiveness, the PACE trial dominates clinical policy in the United Kingdom and other countries, in both government funded health care and private medical insurance.

Background
The PACE trial was funded by the UK Medical Research Council, Department of Health for England, Scottish Chief Scientist Office, and - apparently uniquely for a clinical trial - the Department for Work and Pensions. It cost £5 million and is the most expensive piece of research into ME/CFS ever conducted.

Recruitment of patients began in March 2005 and data collection was completed in January 2010. The study protocol was published in BMC Neurology in 2007. The main study outcomes were published in The Lancet in 2011. .

The principal investigators were Peter White, Trudie Chalder, and Michael Sharpe. Although not an author, Professor Simon Wessely advised the authors and provided feedback.

Professor Wessely stated in November 2015 that "there are also more trials in the pipeline".

Study design
641 patients were randomised into four groups in the study. All received specialist medical care (SMC). Patients in one group also received adaptive pacing therapy (APT), and were advised to stay within the limits of activity imposed by the disease to give their bodies the best chance of recovery. The other two groups were both told that they were not ill but deconditioned, and that if they gradually increased their activity, there was nothing to prevent their recovery. The cognitive behavioural therapy (CBT) group focused on addressing their presumed fear of activity while the graded exercise (GET) group focused on increasing their activity in a structured manner, with regular aerobic exercise as the eventual goal.

Patients in the APT, CBT and GET groups were offered up to 14 sessions with a therapist over a six-month period, to support them in following their therapy programmes, with a top-up session at 36 weeks. They also received a lengthy manual explaining their therapy. All participants were offered at least three sessions of SMC.

Patients were assessed at baseline, 12 weeks, 24 weeks and 52 weeks. The main outcome measures were self-rated fatigue and physical function. Secondary measures included the study's objective outcomes such as a six-minute walking test, a fitness test and economic measures including the number of days of work lost due to fatigue, and the receipt of sickness benefits.

Patients were also followed up (using subjective ratings only) at least two years after randomisation.

Findings
The trial's results showed that patients in the CBT and GET groups improved more in self-rated fatigue and physical function than the APT or SMC groups. However, apart from a marginal effect on the six-minute walking test, all of the study's objective measures and and the long-term follow-up data (self-ratings of fatigue and physical function) showed no difference between groups. Because all groups received SMC, this indicates that APT, CBT and GET added nothing to these outcomes and it has been argued that the subjective ratings therefore did not reflect genuine health effects. However, the study authors have continued to interpret the results as indicating that CBT and GET are effective treatments for ME/CFS.

The authors made no claims about patients recovering in their 2011 Lancet paper, though a Lancet editorial did so, as did one of the study authors at a press conference. However, the authors did claim, in a 2013 paper specifically about recovery, that 22% of patients in the CBT and GET groups had recovered following these therapies but critics have pointed out that the authors abandoned in that paper the analyses that they had specified in the study protocol and replaced them with others that used criteria for recovery that were far easier to meet. The study authors have refused to publish the results according to the original analyses or to provide anonymised individual patient-data so that others can conduct the analyses.

There is great controversy about the authors' refusal to release the data underlying this or any other analysis in the study.

Impact
The PACE trial and other studies that use the Oxford case-definition of ME/CFS have had major international impact on popular perceptions of the disease and also on public policies toward treating and researching it.

Media


On February 27, 2011, when the first PACE trial paper was published, researchers Michael Sharpe and Trudie Chalder held a press conference to discuss their findings. Chalder stated, “twice as many people on graded exercise therapy and cognitive behaviour therapy got back to normal.” That assertion has been criticized for grossly overstating the study's actual findings.

The claims made in the study led to uncritical press coverage around the world, including in The Daily Mail, which stated, "Fatigued patients who go out and exercise have best hope of recovery". The New York Times declared "Psychotherapy Eases Chronic Fatigue Syndrome". According to the British Medical Journal's report on the trial, some participants were "cured."

Many other PACE papers followed, although with relatively little attention in the media until October 2015, when long-term follow-up results were published in The Lancet Psychiatry. The Daily Telegraph ran a front page story with the headline, "Exercise and positivity ‘can overcome ME." The piece stated, "Chronic Fatigue Syndrome is not actually a chronic illness and sufferers can overcome symptoms by increasing exercise and thinking positively, Oxford University has found", and quoted Sharpe describing ME as a “self-fulfilling prophesy” that happens when patients live within their limits. . The article was altered many days after publication after public pressure but no formal retraction was made.

In the UK the Science Media Centre is a government-funded body that describes its purpose as being to improve science journalism. Its reporting on ME/CFS has been criticized for bias towards a psychological etiology for the disease.

Research and treatment
The PACE trial dominates clinical policy in the United Kingdom and other countries, both in government funded health care and private medical insurance.

Because the Oxford definition of CFS is very broad, PACE and other studies that use it muddy the research evidence-base with patients with other conditions. It is for this reason that a 2015 report by the U.S. National Institutes of Health called for the Oxford definition to be retired.

PACE and other Oxford-definition studies also have an impact on how ME/CFS patients are treated clinically through their impact on "evidence-based" clinical guidelines. For instance, in the U.K., the primary NHS treatment recommendations (the NICE guidelines) are for cognitive behavioral therapy (CBT) and graded exercise therapy (GET), based largely on the results of Oxford-definition studies. In the U.S., these studies have led a number of medical education providers, including the CDC, to recommend CBT and GET and/or to link poor prognosis to a patient's belief that the disease is organic.

This impact of PACE and other Oxford-definition studies on clinical guidelines is still seen even though the 2015 Institute of Medicine report on ME/CFS stated that the disease is not psychological and iss characterized by a systemic intolerance to even trivial activity. For example, UpToDate's clinical guidelines recommend the IOM criteria for diagnosis but PACE-style CBT and GET for treatment, even though such treatment would be inappropriate for patients diagnosed by the IOM criteria.

Selection of patients
The PACE trial used the Oxford criteria for diagnosis, which many patients and specialist clinicians consider to overly broad. The National Institutes of Health 2015 P2P report on ME/CFS recommended that the Oxford defintion be retired for this reason.

Changing effectiveness and recovery criteria


The authors abandoned their protocol-specified main outcome and recovery analyses partway through the trial and replaced them with others with lower thresholds.

Most notably, they introduced post-hoc "normal ranges" for fatigue and physical function. These ranges have been heavily criticised for having thresholds so low that patients could worsen from trial entry and yet be within these normal ranges. The "normal range" for physical function (measured on the SF-36 100-point scale) was 60 and above, even though patients had to score 65 or lower to enter the trial. A score of 60 is close to the mean physical function score (57) of patients with Class II coronary heart failure.

The PACE authors used the "normal range", in conjunction with other thresholds, to define clinical effectiveness in the Lancet paper and recovery in a later paper in Psychological Medicine.

Results according to the protocol-specified analyses have never been published and all Freedom of Information requests for them or for the underlying data have been refused.

Outcome measures
The study has been criticised for having subjective primary analyses in an unblinded trial. Subjective measures are known to be susceptible to bias, as can arise from expectations and social pressure. The CBT and GET groups, but not the others, were told that there was nothing to stop them from recovering if they gradually increased their activity, and critics have argued that these differential expectations could have inflated their self-assessments.

Conflicts of interest
The forty-two scientists and clinicians who wrote an open letter to the Lancet complaining about the PACE trial criticized the study authors' failure to disclose a potential conflict of interest to trial participants. They wrote:

"'The investigators violated their promise in the PACE protocol to adhere to the Declaration of Helsinki, which mandates that prospective participants be 'adequately informed' about researchers’ “possible conflicts of interest.” The main investigators have had financial and consulting relationships with disability insurance companies, advising them that rehabilitative therapies like those tested in PACE could help ME/CFS claimants get off benefits and back to work. They disclosed these insurance industry links in The Lancet but did not inform trial participants, contrary to their protocol commitment. This serious ethical breach raises concerns about whether the consent obtained from the 641 trial participants is legitimate.'"

Newsletter to participants
The investigators published a newsletter for participants while the trial was still underway. Critics have said that this could have influenced patients' self-reported outcomes. There were a number of positive testimonials from patients in the trials, but they did not name their therapies: the PACE authors have argued that this meant that there would be no bias in favour of CBT and GET but Professor James Coyne has dismissed the idea that bias would be expected to affect the groups equally.

The newsletter did, however, announce that the new NICE guidelines, "based on the best available evidence... recommended therapies [that] include Cognitive Behavioural Therapy, Graded Exercise Therapy and Activity Management." It is unclear what "Activity Management" was: no group had that title in the PACE trial. Dr. Bruce Levin, a professor of biostatistics at Columbia University and an expert in clinical trial design, said, “To let participants know that interventions have been selected by a government committee ‘based on the best available evidence’ strikes me as the height of clinical trial amateurism”.

The newsletter also contained a less than positive assessment of research on the possibility of an infectious component of ME/CFS, including research by Jose Montoya on herpesviruses and by John Chia on enteroviruses, which would have made the rationale for adaptive pacing therapy (APT) less convincing. The newsletter said, for example, "The laboratory work looked convincing, but many patients had significant gastro-intestinal symptoms and even signs, casting some doubt on the diagnoses of CFS being the correct or sole diagnosis in these patients."

An account of another study, however, gave a positive assessment of CBT, saying "cognitive behaviour therapy was associated with an increase in grey matter of the brain and this increase was associated with improved cognitive function".

Uninformed participant consent
Participants who are considering enrolling in a medical trial are typically provided with information about the trial - including possible risks, for example - to allow them to make an informed decision. In the PACE trial protocol the study investigators agreed to abide by the Helsinki Convention, which includes a commitment to adequately inform trial participants of any conflicts of interest the investigators may have:

"'In medical research involving competent human subjects, each potential subject must be adequately informed of the aims, methods, sources of funding, any possible conflicts of interest, institutional affiliations of the researcher, the anticipated benefits and potential risks of the study and the discomfort it may entail, and any other relevant aspects of the study.'"

However, the investigators did not inform patients of any conflicts of interest, despite reporting consultancy and financial relationships with insurance companies in their Lancet paper.

Risks and side effects
A survey conducted by the ME Association in 2012 showed that 74% of patients had their symptoms worsen after a course of GET. In contrast, the PACE trial found no apparently meaningful difference in rates of adverse events between the four trial groups but critics have questioned whether patients actually increased their activity sufficiently in the CBT and GET groups to trigger many serious adverse events: the lack of improvement in the step-fitness test in all groups indicates that this is distinctly possible.

Response to criticism
The trial investigators have written to defend the trial from criticism on a number of occasions, including in response to letters to The Lancet and Psychological Medicine. They have also responded to a 14,000-word critique by public health expert and journalist Dr David Tuller, which he rebutted. He has said, "“The PACE authors have long demonstrated great facility in evading questions they don’t want to answer”.

Professor Simon Wessely has also attempted to defend the trial, once describing it as "a thing of beauty".

Controversy
The PACE Trial has been heavily criticised by patient groups and some researchers and science journalists for a number of methodological problems since its publication.

Renewed interest in the trial came in October 2015 with public health expert and investigative journalist Dr David Tuller's publication on Virology Blog of Trial by Error, a detailed analysis of PACE's methodological problems. The PACE trial investigators' response was followed by a rebuttal by Tuller and a continuing series of criticisms of different aspects of the study.<ref?

Open letter to the Lancet
On November 2015, scientists Ronald Davis, David Tuller, Vincent Racianiello, Jonathan Edwards, Leonard Jason, Bruce Levin and Arthur Reingold wrote an open letter to The Lancet citing major flaws in the original trial publication and asking for an independent re-analysis of the individual-level trial data. . The journal failed to respond.

In February 2016 the open letter was re-published with 36 additional doctors and researchers including: Dharam Ablashi, Lisa Barcellos, James Baraniuk, Lucinda Bateman, David Bell, Alison Bested, Gordon Broderick, John Chia, Lily Chu, Derek Enlander, Mary Ann Fletcher, Kenneth Friedman, David Kaufman, Nancy Klimas, Charles Lapp, Susan Levine, Alan Light, Sonya Marshall-Gradisnik, Peter Medveczky, Zaher Nahle, James Oleske, Richard Podell, Charles Shepherd, Christopher Snell, Nigel Speight, Donald Staines, Philip Stark, John Swartzberg, Ronald Tompkins, Rosemary Underhill, Rosamund Vallings, Michael VanElzakker, William Weir, Marcie Zinn and Mark Zinn.

Petitions
On October 28, 2015, MEAction launched a petition addressed to The Lancet, Psychological Medicine and the PACE trial authors calling for an independent analysis of the data and the retraction of some of the PACE trial's "misleading claims" based on "absurd 'normal ranges' for fatigue and physical function". The petition was closed in February 2016, having gathered 11,897 signatures from people in sixty-four countries.

A US petition to the Agency for Healthcare Research and Quality (AHRQ) and the Centers for Disease Control was also launched, asking government agencies to remove guidelines and recommendations based on PACE and other studies using the Oxford definition of ME/CFS.

Open data commitments
The study authors have been criticised for failing to follow the requirements of the Medical Research Council (who provided significant funding for the trial) to release anonymised trial data.

The 2012 PACE cost-effectiveness paper was published in the journal PLOS One. That journal requires authors, as a condition of submitting their papers, to agree to release the anonymized trial data underlying the paper's analyses upon request. In November 2015 Professor James Coyne made a request to the PACE authors on that basis, but the authors treated his request as a Freedom of Information request and refused it.

Freedom of Information requests
There have been a number of requests for anonymised PACE trial data made under the UK's Freedom of Information Act. The PACE trial investigators have dismissed at least three of these claims as "vexatious"

A ruling by a UK government body, the Information Commissioner's Office (ICO), on 27 October 2015 ordered Queen Mary University of London (QMUL, the institutional base of the PACE trial's lead investigator Peter White) to release the trial data to a patient who had requested it, subject to appeal within 28 days. Three Freedom of Information requests from 2012 and 2013 were included in the ICO decision. QMUL appealed and the case will be decided at a tribunal in April 2016.

The patient consent form was released through a Freedom of Information request.

The investigators have claimed that they have received 150 Freedom of Information requests in relation to the PACE trial, but it has become apparent that this figure was obtained by counting each piece of requested data as a separate request: the true number of Freedom of Information requests is 34.

Richard Horton, editor of The Lancet, stated on 18 April 2011 in an Australian radio interview: "The Freedom of Information requests and the legal fees that have been racked up over the years because of these vexatious claims has added another £750,000 of taxpayers’ money to the conduct of this study".

Data requests from scientists
Professor James Coyne has publicly called for the trial data to be released. He has repeatedly criticized the PACE investigators for failing to abide by modern expectations concerning "open data".

Professor Coyne's own request for the data under was refused and dismissed under the Freedom of Information Act by the study authors as "vexatious" and as having an "improper motive".

Ronald Davis, David Tuller, Bruce Levin, and Vincent Racaniello requested the PACE trial data in December 2015. Their request was rejected by the trial investigators.

Other calls for data release
A number of groups and individuals have called for the release of the PACE data, including those outside the ME/CFS community who advocate "open data" in science. These calls include:


 * 2016: an article, "PACE trial and other clinical data sharing: patient privacy concerns and parasite paranoia", by Leonid Schneider, an independent science journalist.
 * 2016: open letters from British patient charities Action for ME, Invest in ME, ME Association, Tymes Trust, ME Research UK, Hope 4 ME & Fibro NI, the Welsh Association of ME & CFS Support and the 25 Percent ME Group.
 * 2016: an open letter from a Canadian patient group, the National ME/FM Action Network.
 * 2015: a blog post by Professor Andrew Gelman, a statistician at Columbia University, saying "when researchers refuse to share data, and how they came up with it, they lose the right to call what they do science".
 * 2015: a blog post by Richard Smith, former editor of The BMJ, who said that the PACE authors' institutions were "making a mistake.... the inevitable conclusion is that they have something to hide.”.

Allegations of harassment
The PACE trial investigators and Professor Simon Wessely have publicly claimed they have been harassed and subjected to death threats.

However, the PACE authors and their supporters have been accused of blurring the line between genuine harassment and legitimate and widespread criticism of the study. For example, documentation obtained under the Freedom of Information Act from meetings in 2013 that were attended by some of PACE’s principal investigators include a statement that “harassment is most damaging in the form of vexatious FOIs [Freedom of Information requests].” The PACE authors have made it public that they have received many FOI requests for data. They have denied almost all, labelling several as "vexatious".

The criticism of methodology, findings and ethics by patients and others has often been presented by the investigators - and The Lancet - as a malign campaign. In an editorial comment that accompanied letters criticising the trial, The Lancet described the trial as “rigorously conducted” and questioned whether the “coordination of the response... has been born... from an active campaign to discredit the research”. In an interview on Australian national radio shortly after publication, Dr Richard Horton, the Lancet’s editor, described patients who criticised the trial as “a fairly small, but highly organised, very vocal and very damaging group of individuals”.

But some accuse the investigators of a campaign against patients, labelling them as harassers to undermine their criticisms of the trial, including Angela Kennedy and public health expert and journalist David Tuller, who has said, “Wrapping themselves in victimhood, [the PACE authors] have even managed to extend their definition of harassment to include any questioning of their science and the filing of requests for data — a tactic that has shielded their work from legitimate and much-needed scrutiny.”

Breaches of patient's data security by study investigators
In 2006 confidential PACE trial patient data was stolen from an unlocked drawer at Kings College London.

Malcolm Hooper documents in Magical Medicine how in 2005 confidential patient data was erroneously released by PACE author Professor Michael Sharpe in relation to another study.

Professor Ronald Davis, Stanford University
Professor Ronald Davis is a world-famous geneticist, known for work that enabled the Human Genome Project.

"“I’m shocked that the Lancet published it…The PACE study has so many flaws and there are so many questions you’d want to ask about it that I don’t understand how it got through any kind of peer review.”"

Professor Bruce Levin, Columbia University
Professor Levin is a professor of biostatistics at Columbia University and an expert in clinical trial design.

"“To let participants know that interventions have been selected by a government committee ‘based on the best available evidence’ strikes me as the height of clinical trial amateurism.”"

Professor Arthur Reingold, University of California, Berkeley
Professor Reingold is Head of Epidemiology at the University of California, Berkeley.

"“Under the circumstances, an independent review of the trial conducted by experts not involved in the design or conduct of the study would seem to be very much in order.”"

Emeritus Professor Jonathan Edwards, University College London
Professor Edwards is internationally known for his pioneering work in establishing B-cell depletion therapy as an effective treatment for rheumatoid arthritis.

"“It’s a mass of un-interpretability to me…All the issues with the trial are extremely worrying, making interpretation of the clinical significance of the findings more or less impossible.”"

Professor Leonard Jason, DePaul University
Leonard Jason is a professor of psychology at DePaul University in Chicago, Illinois, and director of its Center for Community Research

"“The PACE authors should have reduced the kind of blatant methodological lapses that can impugn the credibility of the research, such as having overlapping recovery and entry/disability criteria.”"

Professor James Coyne, University Medical Center, Groningen
Professor Coyne is Professor of Health Psychology, University Medical Center, Groningen and University of the Netherlands; Distinguished Visiting Professor at the Institute for Health Policy, Rutgers, the State University of New Jersey; and Professor Emeritus of Psychology in the Department of Psychiatry, University Of Pennsylvania. He is one of the most cited psychologists in the academic literature.

"'The data presented are uninterpretable. We can temporarily suspend critical thinking and some basic rules for conducting randomized trials (RCTs), follow-up studies, and analyzing the subsequent data. Even if we do, we should reject some of the interpretations offered by the PACE investigators as unfairly spun to fit what has already a distorted positive interpretation of the results.'" "'The self-report measures do not necessarily capture subjective experience, only forced choice responses to a limited set of statements.'" "'One of the two outcome measures, the physical health scale of the SF-36 requires forced choice responses to a limited set of statements selected for general utility across all mental and physical conditions.'" "'Despite its wide use, the SF-36 suffers from problems in internal consistency and confounding with mental health variables. Anyone inclined to get excited about it should examine its items and response options closely. Ask yourself, do differences in scores reliably capture clinically and personally significant changes in the experience and functioning associated with the full range of symptoms of CHF?'" "'The validity other primary outcome measure, the Chalder Fatigue Scale depends heavily on research conducted by this investigator group and has inadequate validation of its sensitivity to change in objective measures of functioning.'" "'Such self-report measures are inexorably confounded with morale and nonspecific mental health symptoms with large, unwanted correlation tendency to endorse negative self-statements that is not necessarily correlated with objective measures.'"

Professor Coyne gave a public talk criticising the PACE trial in Edinburgh in November 2015. Video footage is available , as are a full and an edited transcript and an audio recording

He spoke again about the PACE study in Belfast in February 2016 where he described it as "a wasteful trainwreck of a study".

Professor Coyne has questioned whether the PACE trial paper could ever have been properly peer-reviewed, given the large number of study authors and the small world of British science.

Professor James Coyne, University Medical Center, Groningen & Professor Keith Laws, University of Hertfordshire
Professors Coyne and Laws have criticised, in a joint letter to Lancet Psychiatry, the long-term follow-up analysis of the PACE trial that was published in 2015: Referring to the results of the study as a whole, they said:

"'There are no group differences, and the overall mean short-form 36 (SF-63) physical functioning score is less than 60. It is useful to put this number in context. 77% of the PACE trial participants were women, and the mean age of the trial population was 38 years, with no other disabling medical conditions. Patients with lupus have a mean physical functioning score of 63,2 patients with class II congestive heart failure have a mean score lower than 60,3 and normal controls with no long-term health problems have a mean score of 93.'"

Dr. Charles Shepherd, ME Association
Dr Shepherd, medical advisor to the ME Association, has criticised the trial's long-term follow-up analyses. "'Without robust objective evidence relating to improvement and recovery, the ME patient community will continue to regard the PACE trial as a tremendous waste of research funding money'"

Dr David Tuller, University of California, Berkeley
Dr Tuller is is academic coordinator of UC Berkeley's joint masters program in public health and journalism. He was a reporter and editor for 10 years at the San Francisco Chronicle, served as health editor at Salon.com and frequently writes about health for The New York Times. He has written extensively about the PACE trial.

"'The study included a bizarre paradox: participants’ baseline scores for the two primary outcomes of physical function and fatigue could qualify them simultaneously as disabled enough to get into the trial but already “recovered” on those indicators–even before any treatment. In fact, 13 percent of the study sample was already “recovered” on one of these two measures at the start of the study.'"

"'In the middle of the study, the PACE team published a newsletter for participants that included glowing testimonials from earlier trial subjects about how much the “therapy” and “treatment” helped them. The newsletter also included an article informing participants that the two interventions pioneered by the investigators and being tested for efficacy in the trial, graded exercise therapy and cognitive behavior therapy, had been recommended as treatments by a U.K. government committee “based on the best available evidence.” The newsletter article did not mention that a key PACE investigator was also serving on the U.K. government committee that endorsed the PACE therapies.'"

"'The PACE team changed all the methods outlined in its protocol for assessing the primary outcomes of physical function and fatigue, but did not take necessary steps to demonstrate that the revised methods and findings were robust, such as including sensitivity analyses. The researchers also relaxed all four of the criteria outlined in the protocol for defining 'recovery.' They have rejected requests from patients for the findings as originally promised in the protocol as 'vexatious.''"

"'The PACE claims of successful treatment and “recovery” were based solely on subjective outcomes. All the objective measures from the trial—a walking test, a step test, and data on employment and the receipt of financial information—failed to provide any evidence to support such claims. Afterwards, the PACE authors dismissed their own main objective measures as non-objective, irrelevant, or unreliable.'"

"'In seeking informed consent, the PACE authors violated their own protocol, which included an explicit commitment to tell prospective participants about any possible conflicts of interest. The main investigators have had longstanding financial and consulting ties with disability insurance companies, having advised them for years that cognitive behavior therapy and graded exercise therapy could get claimants off benefits and back to work. Yet prospective participants were not told about any insurance industry links and the information was not included on consent forms. The authors did include the information in the “conflicts of interest” sections of the published papers.'"

"'The Lancet Psychiatry follow-up had null findings: Two years or more after randomization, there were no differences in reported levels of fatigue and physical function between those assigned to any of the groups.... Yet the authors, once again, attempted to spin this mess as a success.'"

Dr David Tuller, University of California, Berkeley & Julie Rehmeyer, journalist
Public health expert Dr Tuller and ME/CFS patient Julie Rehmeyer are both journalists who have written critically about the PACE authors' claims regarding the safety of Graded exercise therapy. :

"'The study’s primary case definition for identifying participants, called the Oxford criteria, was extremely broad; it required only six months of medically unexplained fatigue, with no other symptoms necessary. Indeed, 16% of the participants didn’t even have exercise intolerance—now recognized as the primary symptom of ME/CFS'"

"'After the trial began, the researchers tightened their definition of harms, just as they had relaxed their methods of assessing improvement.'"

"'the study was unblinded, so both participants and therapists knew the treatment being administered. Many participants were probably aware that the researchers themselves favored graded exercise therapy and another treatment, cognitive behavior therapy, which also involved increasing activity levels. Such information has been shown in other studies to lead to efforts to cooperate, which in this case could lead to lowered reporting of harms.'"

Tom Kindlon, Irish ME Association
Mr Kindlon is a patient who has published extensive criticism of the PACE trial. In 2011 he published a paper on harms associated with Graded exercise therapy.

Dr Ellen Goudsmit, retired health psychologist
Dr Goudsmit has published a number of criticisms of the PACE trial.

"'The PACE trial was scientifically extremely poor'"

"'A treatment like GET is simply not appropriate for a disease like ME which is linked to infection and metabolic abnormalities. Given the close relationship between exertion and symptoms, it follows that asking a patient to increase their activity levels is as logical as advising smokers with lung cancer to gradually increase the number of cigarettes they smoke'"

Frank Twisk, ME-de-patiënten Foundation
Dutch patient Frank Twisk has also published criticism of the PACE trial.

"'The PACE trial investigated the effects of CBT and GET in chronic fatigue, as defined by the Oxford criteria, not in chronic fatigue syndrome, let alone myalgic encephalomyelitis'"

"'the positive effect of CBT and GET in subjective measures, fatigue and physical functioning, cannot be qualified as sufficient. Mean short form-36 physical functioning scores in the CBT group (62·2) and the GET group (59·8) at follow-up were below the inclusion cutoff score for the PACE trial (≤65)3 and far below the objective for recovery as defined in the PACE protocol (≥85)'"

"'The vast majority of patients improved subjectively by specialist medical care and APT to the same level as by CBT and GET, without any additional therapies, including CBT and GET, or by other therapies'"

"'looking at subjective outcomes at follow-up1 and objective outcomes in earlier studies, such as physical fitness,2 return to employment,3 social welfare benefits,3 and health-care usage,3 CBT and GET, like specialist medical care and APT, cannot be qualified as effective'"

Robert Courtney
Mr Courtney has written a number of published letters in the medical journals, criticising PACE.

"'Chalder and colleagues acknowledge that the trial outcomes do not support the hypothetical deconditioning model of GET for chronic fatigue syndrome'"

Analysis by patient "citizen-scientists"
Several patients have produced critiques of PACE's statistical analyses, trial methodology and ethics.

Graham McPhee, Tom Kindlon and others have collaborated on a set of explanatory videos about flaws in PACE's statistical analyses:


 * The PACE Race
 * 60 - The new 75
 * Not so bad
 * The force of LOGic

Graham McPhee and Janelle Wiley also collaborated with others to create a website summarising their critical findings.

Tom Kindlon has also has written a large number of letters and comments that have been published in medical journals in response to the published papers.

Among many other published letters that have been critical of the trial, many are from people who have identified themselves as patients. For example, most of the letters published by The Lancet criticising the 2011 PACE paper were from patients or representatives of patients' groups.

Peter Kemp has written a detailed critique of the study.

MEAction has published an overview of PACE and its flaws, produced by patients.

Principal investigators and researchers
The principal investigators on the PACE trial are Professors Peter White, Trudie Chalder and Michael Sharpe. Additional authors on the 2011 Lancet paper are K.A. Goldsmith, A.L. Johnson, L. Potts, R. Walwyn, J.C. DeCesare, H.L. Baber, M. Burgess, L.V. Clark, D.L. Cox, Jessica Bavinton, B.J. Angus, Gabrielle Murphy, M. Murphy, H. O'Dowd, D. Wilks, and P. McCrone,.

2007: PACE trial protocol
BMC Neurology published the trial's planned methodology, including its planned analyses.

2011: Main trial outcomes
The trial's main outcomes, and some selected secondary outcomes, were reported in The Lancet. Forty-four letters were submitted, in a response that the journal's editor described as "swift and damning".

2012: Cost-effectiveness of CBT and GET
This paper was published in PLOS One. Controversy has broken out over the failure of the study authors to provide the underlying data to Professor James Coyne under PLOS One's data-sharing policy.

2013: "Recovery" rates
This paper appeared in Psychological Medicine. The Science Media Centre issued an "expert opinion" about the study.

ME/CFS patient Graham McPhee and others created a video animation explaining problems with the new analyses that had replaced those specified in the study protocol: How's that recovery?. Sam Carter applied the PACE study recovery criteria to the data from the FINE trial and questioned whether recovery had been improved six-fold by moving the threshold.

Patient-advocate Peter Kemp also criticized the study, stating that the authors had "twisted the SF-36 Physical Function subscale to suit their needs".

2013: Statistical analysis plan
Trials Journal published the detailed plan for PACE's data analysis.

2014 Adverse Effects Paper
This 2014 paper published in the Journal of Psychosomatic Research examined adverse effects and deterioration.

2015 Secondary Mediation Analysis
This 2015 paper was published in The Lancet Psychiatry. (Trudie Chalder, Goldsmith KA, Peter White, Michael Sharpe, Pickles AR)

The paper has been criticised by Byron Hyde.



2015 Long-term Follow-up Paper
A long-term follow-up paper was then published in The Lancet Psychiatry in October 2015. .

This paper states that after 2.5 years "there were no significant differences" in outcomes between the treatment groups.

The Science Media Centre published expert opinion on the paper.

The study was criticized by James Coyne and Keith Laws as being "uninterpretable", and described the results as "null findings". The ME Association also criticized the follow-up study.

2015 Longitudinal Mediation Paper
This short paper published in Trials Journal on 16 November 2015 concludes "Approximately half of the effect of each of CBT and GET were on physical function was mediated through reducing avoidance of fearful situations".

Other Publications

 * 2014, Pain in chronic fatigue syndrome: response to rehabilitative treatments in the PACE trial
 * 2013, The planning, implementation and publication of a complex intervention trial for chronic fatigue syndrome: the PACE trial
 * 2013, Cognitions, behaviours and co-morbid psychiatric diagnoses in patients with chronic fatigue syndrome
 * 2013, Training, Supervision & Therapists' Adherence to Manual Based Therapies
 * 2011, Measuring disability in patients with chronic fatigue syndrome: reliability and validity of the Work and Social Adjustment Scale
 * 2010, Psychiatric misdiagnoses in patients with chronic fatigue syndrome

Talks & interviews

 * 2016, Dr. David Tuller discusses the flaws of the PACE trial (see also David Tuller)

Learn more

 * Wikipedia - Chronic fatigue syndrome treatment
 * 2016, ‘It was like being buried alive’: battle to recover from chronic fatigue syndrome
 * 2016, PACE trial and other clinical data sharing: patient privacy concerns and parasite paranoia
 * 2016, TULLER: PACE AUTHORS “WRAPPING THEMSELVES IN VICTIMHOOD”
 * 2016, PACE trial's forbidden fruit - is the data really poisonous?
 * 2011, Radio National Australia (April 18)
 * 2011, Expert Opinion (Science Media Centre, February 17)
 * 2011, Study finds therapy and exercise best for ME (author Trudie Chalder stated "twice as many people on graded exercise therapy and cognitive behaviour therapy got back to normal")