Trial By Error: PEM Is Bad and So Is Fukuda, New Study Finds

By David Tuller, DrPH

A new study in the Journal of Psychosomatic Research, posted December 16th, has reported that patients with chronic fatigue syndrome who experience major post-exertional malaise have a greater burden of psychological distress than those whose PEM is minimal or non-existent. Of course, this is not surprising. The sicker people are, with this or any illness, the more likely it is they will  experience depression or related emotional turmoil for any number of reasons, the impacts of poor health, discrimination at work, lack of understanding from family and friends, etc.

Yet the paper couches these findings in language that suggests patients are possibly or likely responsible for keeping themselves sick. And the authors appear to overlook the main implications of their own findings.

The corresponding and senior authors are from the psychology department of the University of Miami. Co-authors include Nancy Klimas and Mary Anne Fletcher from Nova Southeastern University, in Fort Lauderdale. (In what appears to be an error, Dr Klimas and Dr Fletcher are listed in the author credits as being affiliated with NSU’s psychology department, when the university’s website indicates that both are affiliated with the Dr. Kiran C. Patel College of Osteopathic Medicine. The journal has reviewed and accepted the article, but it is still “in press” and the available text is the “pre-proof,” so perhaps it is still undergoing corrections.)

For the study, the authors examined data from 261 patients diagnosed with the so-called Fukuda-CDC criteria. This 1994 case definition predominated in clinical care and research for decades but is increasingly being supplanted by newer (and also often contested) criteria. Fukuda requires prolonged fatigue plus four of eight other symptoms. PEM is one of the eight; that means people can be defined with the illness but not have PEM at all. Newer criteria all require the presence of some form of PEM, however defined.

In the symptom questionnaire completed by patients in the JPR study, PEM was identified as €œunusual fatigue following exertion that lasts for at least 24 hours.€ Patients were split into two groups based on their PEM experience. The 139 patients who described their PEM as €œsevere€ or €œvery severe” were compared to the 122 who described it as €œmoderate,€ €œmild,€ or €œvery mild,€ or who did not indicate that they had it at all.

Not surprisingly, patients who reported worse PEM also scored more poorly on various dimensions measured, both physical and psychological. As the authors write: €œThis study replicates the association between PEM and symptom burden and additionally associates PEM with psychological distress.€ The measures of psychological distress included indicators of €œsocial disruption, depressive symptoms, and mood disturbance.€

Of course, like anyone with or without a debilitating chronic illness, patients might benefit from some form of psychotherapy or counseling to address mood disorders and related issues, whether arising as a direct result of being sick or from other factors. And yet the JPR paper suggests, without apparent evidence, that these psychological matters themselves might be impeding the ability of CFS patients to recover.

Here€™s what the authors write in their introduction: €œAs a general exacerbation of CFS symptoms, PEM is likely to have substantial effects on patients€™ quality of life and be uniquely distressing in psychological terms. It is also possible that PEM inhibits patients from engaging in physical or cognitive exertion, thereby precluding them from the benefits of such pursuits and sustaining the expression of CFS. Seen in this light, PEM could play a role in the maintenance of CFS phenomenology by way of its psychological effects.€


And this line of argumentation continues in the discussion section: €œBecause this psychological distress is a potential maintaining factor of CFS (i.e., by inhibiting patients from engaging in tasks requiring physical or cognitive exertion and thereby compromising quality of life), PEM may also identify those patients who are in the greatest need of and would potentially benefit the most from psychological intervention.€

In a neutral context and with regular diseases, this framing and phrasing might not trigger alarm bells. However, when it comes to CFS or ME or the illness (or cluster of illnesses) variously meant by these terms and others, there is obviously a long and sorry back-history of patient-blaming that parallels this line of argumentation. What the JPR authors suggest here clearly resembles the unsupported ruminations and ramblings of the CBT/GET ideological brigades. The apparent assumption is that patients are exacerbating their condition through an avoidance of activity, rather than that they avoid activity because that€™s how they avoid exacerbating their condition.

The paper itself offers no coherent explanation for why this activity avoidance and the consequent “compromising of quality of life” have been construed as being a €œmaintaining factor of CFS.€ What is the mechanism by which this purported maintenance of CFS symptomology occurs? The authors present the proposition as if this claimed causal pathway from sedentary behavior to perpetuation of illness is, you know, uncontested–something we all agree on. That assumption should have been challenged by reviewers, editors or anyone who read the draft.

Yet when a published paper gets its own declared €œhighlights€ wrong, readers can be forgiven for wondering whether other things might be amiss. One of the study€™s four stated highlights is this: €œResults suggest the Fukuda case definition does not define a heterogeneous group.€

In fact, that€™s the exact opposite of what the study found; according to the authors, the results demonstrated €œthe heterogeneity of diagnoses resulting from the Fukuda criteria.€ In the highlight, the word “heterogeneous” should clearly be replaced with “homogeneous.”

Whatever the psychological outcomes, the study’s findings suggest that the Fukuda case definition identifies many people who might not in fact have the illness in question. The authors themselves write that, per their results, €œincluding PEM as a polythetic criterion for CFS is inappropriate.€ Yet they do not press that observation to its obvious end-point–which is that any case definition used to identify patients should require the presence of PEM. Instead, the authors call for research comparing how patients with and without severe PEM respond to psychological interventions.

So as far as I can tell, the main message of this paper is, or should be, that the Fukuda case definition is inadequate because many of those who meet it do not appear to experience PEM as a debilitating factor, if they experience it at all. Given that PEM is already viewed as the cardinal symptom of the illness, the logical conclusion is that such patients don€™t have ME, despite having been diagnosed with CFS per Fukuda. As it reads, the study€™s main finding seems to be that CFS patients with PEM need psychological intervention, when in fact what they really need most is effective medical treatments for their ME.

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