Research bias in ME/CFS

Research in every field deals with bias. Research into myalgic encephalomyelitis/chronic fatigue syndrome faces specific kinds of bias issues as it navigates significant gaps in scientific knowledge and several opposing viewpoints.

Emphasis on randomized controlled trials and systematic reviews

Following an Evidence-Based Medicine (EBM) model gives greater weight to systematic reviews and randomized controlled trials.

PACE trial

Davenport et al. (2018) state the lack of randomized controlled trials in ME/CFS research mean that an evidence-based model can be unduly influenced by a very small number of studies, for example the PACE trial found that treating ME/CFS with graded exercise therapy or cognitive behavioral therapy did not result in clinically significant improvements - but this trial heavily influenced the clinical use of those treatments. The PACE trial was so problematic that it was used an the example for Prof. Bruce Levin's presentation How Not To Conduct A Randomized Clinical Trial, and The Lancet received open letters signed by over 100 people, including researchers and academics, calling for the trial to be retracted.

Cochrane systematic review

The highly influential Cochrane review of exercise therapy for chronic fatigue syndrome was also found to have significant flaws.

Bias recognition

Geraghty et al. (2019) looked at evidence behind the popular cognitive behavioral model of ME/CFS, and found that a number of research papers contained significant evidence that did not support the model combined with contradictory abstracts or conclusions at odds with the authors' results, and notable selective interpretation of evidence, such as ignoring any contradictory research.

Sonia Lee (PhD, University of Sydney) assessed research waste in ME/CFS by comparing the PACE trial with two cellular trials, finding that "selective reporting", an indicator of research waste, was greater in the PACE trial; however this paper (2017) was not peer-reviewed.

Nacul et al. (2017) discussed the effects of selection bias, highlighting how psychosocial/biopsychosocial studies frequently used the broadest diagnostic criteria - the Oxford criteria - and did not break results down by subgroup. The use of the Oxford criteria lead to a 100-fold increase in disease prevalence compared to the Canadian Consensus Criteria (CCC); with 14 out of 15 patients meeting the Oxford criteria typically failing to meet the Canadian Consensus Criteria for ME/CFS.

Notable studies

• 1982, Suffering and the Social Construction of Illness: The Delegitimation of Illness Experience in Chronic Fatigue Syndrome (Abstract)

• 2005, Chronic Fatigue Syndrome: Editorial Bias in The Lancet (Abstract) - Not peer-reviewed

• 2011, Chronic Fatigue Syndrome: Editorial Bias in the British Medical Journal (Abstract)

• 2017, Bias, misleading information and lack of respect for alternative views have distorted perceptions of myalgic encephalomyelitis/chronic fatigue syndrome and its treatment (Full Text)

• 2017, How have selection bias and disease misclassification undermined the validity of myalgic encephalomyelitis/chronic fatigue syndrome studies? (Full text)

• 2017, Research Waste in ME/CFS (Full text) - not peer reviewed
• 2018, Checking our blind spots: current status of research evidence summaries in ME/CFS (Abstract) - Editorial
• 2018, Are ME/CFS Patient Organizations "Militant"? : Patient Protest in a Medical Controversy. (Abstract)
• 2019, The ‘cognitive behavioural model’ of chronic fatigue syndrome: Critique of a flawed model (Full text)

Articles and blogs

• 2017, PACE team response shows a disregard for the principles of science - Jonathan Edwards

• 2017, MEA Review: The SMILE trial - a lesson in how not to conduct clinical trials in people with ME/CFS (Full text) - by Dr Charles Shepherd, ME Association medical advisor

See also

• Clinical trial terminology (category)
• Research terminology (category)
• Bruce Levin
• Wessely school
• Ethical issues
• Ben Goldacre

bias Bias in research is "a systematic deviation of an observation from the true clinical state". (Learn more: me-pedia.org)

randomized controlled trial (RCT) - A trial in which participants are randomly assigned to two groups, with one group receiving the treatment being studied and a control or comparison group receiving a sham treatment, placebo, or comparison treatment.

PACE trial A controversial study which claimed that CBT and GET were effective in treating "CFS/ME", despite the fact that its own data did not support this conclusion. Its results and methodology were widely disputed by patients, scientists, and the peer-reviewed scientific literature.

bias Bias in research is "a systematic deviation of an observation from the true clinical state". (Learn more: me-pedia.org)

Canadian Consensus Criteria (CCC) - A set of diagnostic criteria used to diagnose ME/CFS, developed by a group of practicing ME/CFS clinicians in 2003. The CCC is often considered to be the most complex criteria, but possibly the most accurate, with the lowest number of patients meeting the criteria. Led to the development of the International Consensus Criteria (ICC) in 2011.

cognition Thought processes, including attention, reasoning, and memory.

subjective outcome An outcome of a clinical trial that depends on the judgement or opinion of the assessor or patient, e.g. asking if fatigue has increased or decreased "a little" or "a lot", patient questionnaires like the Chalder Fatigue Scale, and other patient-reported outcome measures (PROMs).