Comparing Operationalized Approaches for Substantial Reduction of Functioning in CFS and ME, 2022, Wiedbusch and Jason

Full title:
Comparing Operationalized Approaches for Substantial Reduction of Functioning in Chronic Fatigue Syndrome and Myalgic Encephalomyelitis

Abstract

A core criterion for Chronic Fatigue Syndrome (CFS) and Myalgic Encephalomyelitis (ME) is a substantial reduction in functioning from pre-illness levels. Despite its ubiquity in diagnostic criteria, there is considerable debate regarding how to measure this domain. The current study assesses five distinct methods for measuring substantial reductions.

The analysis used an international, aggregated dataset of patients (N = 2,368) and controls (N=359) to compare the effectiveness of each method. Four methods involved sophisticated analytic approaches using the Medical Outcomes Survey Short Form-36; the fifth method included a single self-report item on the DePaul Symptom Questionnaire (DSQ).

Our main finding was that all methods produced comparable results, though the DSQ item was the most valid in differentiating patients from controls. Having a simple, reliable method to capture a substantial reduction in functioning has considerable advantages for patients and health care workers.

Open access: https://scholars.direct/Articles/community-medicine/acm-4-012.php

 

A couple of extracts that I thought were interesting

"The DSQ's item may allow researchers to avoid some of the current problems with case definitions and their varying guidelines. For example, in the Myalgic Encephalomyelitis International Consensus Case Criteria (ME-ICC), Carruthers and colleagues (2011) [18] operationalized substantial reduction into three severity categories. The "mild" level indicated an approximate 50% reduction in a patient; "moderate" suggested patients are mostly housebound; "severe" to "very severe" signified that a patient is mostly or entirely bedridden.

The following year, Carruthers, et al. (2012) [19] developed a primer using the ME-ICC criteria for medical practitioners to diagnose patients with ME/CFS. However, the primer differed from the previous year's guidelines in the ME-ICC [20]. The original description of this criteria in the ME-ICC [18] designates "mild" as an approximate 50% reduction, while the ME primer [19] defines the "moderate" level as a 50% reduction. It is evident that determining consistent standards for this criterion is challenging, even when case definitions attempt to operationalize these criteria."

and

"It is worth noting that the Diagnostic and Statistical Manual of Mental Disorders primarily uses a substantial reduction criterion for diagnosing mental disorders [20]. Physical illnesses do not require patients to prove impairments in levels of functioning, so it is unclear whether this is necessary for those with ME/CFS. Indeed, the substantial reduction criterion may be stigmatizing to individuals with ME/CFS, as it denotes that patients must prove impairment to medical professionals [1,9]. However, as it is part of almost all ME/CFS case definitions, finding appropriate ways to measure it is of importance for health care workers."

 

Interesting point about having to prove impairment.

The requirement for substantially reduced functioning for diagnosis has always seemed strange to me. To my mind you either have whatever pathological processes underlie ME or you don't. That applies even if you're lucky enough to function at 90%. If you get PEM every time you go over your 90% limit, that still points to ME and you need to know this because you're at risk of worsening if you go over your limit too much.

Level of functioning is certainly highly relevant for working out what sort of financial and practical support a pwME needs (not that need necessarily translates into actually getting). Level of functioning, looked at as part of the package of symptoms, may well be helpful when making a diagnosis but it shouldn't be required for one.

 

None of the cut off scores allows separation of cognitive disability from overall physical functioning. It leaves the possibility for someone to be substantially impacted by cognitive deficits while still recording only limited overall reduction in function. Ironically the paper says:

"There are some limitations in the implications and methods of this study. Many patients with ME/CFS have neurocognitive difficulties, which could affect their ability to recall prior levels of functioning [21,22]. Thus, many patients might have difficulties accurately measuring these reductions and their levels of premorbid functioning in a self-report assessment."

So the authors recognise that patients may be so cognitively affected as to make completing a questionnaire accurately a challenge but don't identify impaired cognition as a source of reductions in functioning that may be present separately from the headings of: physical functioning, role physical(sf 36), social functioning and general health. SF36 has no elements that identify cognitive impairments and the De Paul Questionnaire has 9 cognition related questions out of 99 but does not seem structured to allow these to be expressed as a separate domain.

 

From the article:

" Physical illnesses do not require patients to prove impairments in levels of functioning, so it is unclear whether this is necessary for those with ME/CFS."

This statement is puzzling. My understanding is, level of impairment is always considered important by disability adjudicators.

Disability insurance claimants, including pwME, have been sent to rehab centres where they are put through physical tests to ascertain their functioning. A snapshot of how the claimant functions for a short period of time. With no view at all of how the person is the next day, or how they function in real life situations. But nonetheless, a so-called examination of their level of functioning/impairment.

Page 15 of the Canadians Consensus Criteria has the patient or the medical practitioner rate the level of symptoms as absent, mild, moderate or severe:

https://www.mefmaction.com/images/stories/Overviews/ME-Overview.pdf

A difficult task as it is also suggested that the pwME rank the symptoms in severity order.

As @CRG has pointed out, it's a problem to complete a questionnaire with cognitive impairment many pwME suffer from.

It's also difficult to decide on the severity ranking due to the vacillation of symptoms experienced.

Completing this form, may give the medical practitioner some idea of level of impairment.

The 2- day-CPET, the tilt table test, the impedance cardiograph test etc., may also provide information re functional impairment.

Without these tests, which many practitioners do not have access to, determining a level of functional impairment can be challenging.

I agree with the authors, it is important to find ways to measure the impairment in ME.

Given the lack of interest and funding for this illness, the difficulty in measuring impairment remains.

ETA: Changed "the" to "a"

 

I thought the 50% reduction was for Social Security Disability claims. If a person is only 25% reduced, then they lose their disability case. They are told to change professions to an easier job. During one of my disability reviews a psychiatrist hounded me over the percentages.

 

My disability benefits claim early on (w/o cognitive impairment and PEM at the time) was based on my history of relapsing-remitting M.E, and not 'mild, moderate or severe' category.

 

If an authority aims to decide how disabled or functionally impaired a pwME is, it's quite possible that they do not know ME is variable and unpredictable. A pwME may go along for even a few days appearing to do normal tasks. Then, fall apart and crash because they have done too much. It may take them days, weeks or more to recover. To indicate a pwME can dependably work, or attend to other activities at certain times of the day, or for a certain number of days per week is very mistaken. They really do not understand ME at all.