Latest research: criteria, course of illness and more
January 25, 2018
Supporting you to stay informed about M.E. research, we publish regular round-ups from Action for M.E. volunteer and pharmacist Emily Beardall, covering a selection of papers published in peer-reviewed journals.
Please note this is not an exhaustive list – we have selected to highlight the studies that we think are most likely to resonate with the daily lives of those affected by the condition. We will also report separately on further studies of significance, as and when they are published. You can search online directory PubMed for most studies about M.E. published in peer-reviewed journals.
The following studies were published online between 17 October 2017 and 16 January 2018. In each case, we have used the same name for the illness as the researchers publishing the paper.
Diagnostic and research criteria
An article in the journal Fatigue by the UK M.E./CFS Biobank team explains the problems caused by having numerous criteria for diagnosing the illness and selecting participants for research. Research using wider criteria, such as participants needing to have had fatigue for over six months, may include patients who do not have true M.E./CFS. This makes clinical trial results seem inconclusive and has also led to one-size-fits-all approaches, such as cognitive behaviour therapy and graded exercise therapy, being seen as treatments rather than management options.
The authors ask that seemingly effective management options should not distract researchers and clinicians from the need for biomedical research into the cause of the illness and effective drug treatments.
“It is difficult for both researchers and those with M.E./CFS not to be left with a sense of frustration and loss when reflecting on the time and resources invested in studies using more generalised, and we argue, less productive criteria such as that contained in the Oxford definition,” say the authors. “If M.E./CFS participants who are more likely to be ‘true cases’ are recruited with standardised procedures and robust data collection for clinical phenotyping across research groups, significant advances in the understanding of ME/CFS are likely to follow.”
The energy-envelope theory
The theory that keeping well within a person’s available energy can lead to a gradual improvement in M.E./CFS was tested in a study published in the journal Chronic Illness. Those who under-used their available energy were found to be less disabled and have better symptom and functioning scores. The study also found that those with higher energy levels were more likely to over-do it, causing worsening of symptoms, so the authors suggest that overexertion may counteract the benefit of having higher energy levels.
The authors suggest that the Envelope Theory may be most helpful for people who are pushing themselves beyond their energy limitations or that have severe energy limitations. They also point out that the findings contradict the argument that reducing activity causes symptoms to worsen via deconditioning.
Factors affecting illness severity and length
A study in the journal BMC Public Health investigated the factors affecting the severity and duration of illness. Based on in-depth interviews of 26 people with post-infectious fatigue syndrome (PIFS) following an outbreak of enteritis in Norway, a number of factors were identified. We have included this study here as the authors explain that PIFS is “also termed post-viral fatigue syndrome (PVFS) or myalgic encephalomyelitis (M.E.)” and that in “the case definition used to diagnose the affected persons, the term chronic fatigue syndrome (CFS) is used.”
Factors related to external sources – healthcare and welfare systems, health care providers and society – included misdiagnosis, trivialisation of symptoms, unhelpful advice, delayed diagnosis and lack of appropriate help. Internal factors – ie. relating to each individual’s personal experience of the illness – were lack of knowledge, overestimating functional capacity, assuming the condition will pass, ignoring body signals and denial. The authors hope their findings will help healthcare services to deliver improved care leading to faster recovery, increased functioning and returning to their pre-illness life.
Emily comments: “In this paper, the authors make it clear that the internal factors are not about blaming the patients. Instead, patients’ tendency to overestimate their capacity and deny the reality of their symptoms are a direct result of not being believed, and having their health problems minimised or dismissed. Many of us have internalised this, training ourselves not to take our own illness or symptoms seriously, because of how we have been treated.”
Course of illness
A study in the Journal of Biosensors, Biomarkers and Diagnostics asked adults with a current diagnosis of M.E. or CFS about the progression of their illness. Around two thirds (60%) described their illness as “fluctuating.”
Those reporting that they were “constantly getting worse” (16%) or “persisting” (14%), so not changing over time, were the next largest groups, while 9% said their illness was “relapsing and remitting,” meaning that they have good periods with no symptoms but relapses. Only 2% said they were “constantly getting better.” The authors suggest that this may be an effective way of putting people with M.E. and CFS into sub-groups for further research.
Energy metabolism in the brain
A study in the journal Fatigue examined the levels of lactate in the fluid in cavities in the brain called the ventricles. Lactate is a by-product of anaerobic energy metabolism, when there is no oxygen available. The study compared ventricular lactate in participants with CFS alone, fibromyalgia alone, overlapping CFS and fibromyalgia, and healthy controls.
There was no distinction between lactate levels in the three groups of patients, but their levels were significantly higher than in the healthy controls. Although accumulations of lactate were found in both CFS and fibromyalgia, the authors state this may not be for the same underlying reason, as this can occur either as a result of anaerobic metabolism or as a result of neuro-inflammation and that further studies are needed to find this out.