Systematic Review of the Epidemiological Burden of ME/CFS Across Europe: Current Evidence and EUROMENE Research Recommendations for Epidemiology 2020

[Sly Saint]

Systematic Review of the Epidemiological Burden of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Across Europe: Current Evidence and EUROMENE Research Recommendations for Epidemiology

Abstract
This review aimed at determining the prevalence and incidence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) in Europe. We conducted a primary search in Scopus, PubMed and Web of Science for publications between 1994 and 15 June 2019 (PROSPERO: CRD42017078688).

Additionally, we performed a backward-(reference lists) and forward-(citations) search of the works included in this review. Grey literature was addressed by contacting all members of the European Network on ME/CFS (EUROMENE). Independent reviewers searched, screened and selected studies, extracted data and evaluated the methodological and reporting quality. For prevalence, two studies in adults and one study in adolescents were included. Prevalence ranged from 0.1% to 2.2%. Two studies also included incidence estimates. In conclusion, studies on the prevalence and incidence of ME/CFS in Europe were scarce.

Our findings point to the pressing need for well-designed and statistically powered epidemiological studies. To overcome the shortcomings of the current state-of-the-art, EUROMENE recommends that future research is better conducted in the community, reviewing the clinical history of potential cases, obtaining additional objective information (when needed) and using adequate ME/CFS case definitions; namely, the Centers for Disease Control & Prevention−1994, Canadian Consensus Criteria, or Institute of Medicine criteria.

https://www.mdpi.com/2077-0383/9/5/1557

 

[cassava7]

3 studies were included in their screening, the results are too different to be interpreted.

Among the included studies in adults using the CDC−1994 case definition, prevalence estimates ranged from 0.2% [26] to 2.2% [13].
[...] these large variations in estimates may be a consequence of differences in methods, in inclusion/exclusion criteria, and in case definitions of ME/CFS.

The article correctly assesses that:

One of the studies included in the present review found that initial diagnoses of ME/CFS made by General Practitioners (GPs) were usually inaccurate, which impacts the estimation of the prevalence of ME/CFS [26]. Potential reasons for misdiagnosis include limited knowledge of or inability to recognise ME/CFS, and lack of access for patients with severe ME/CFS symptoms to GPs or other healthcare professionals [31]. In Europe, many primary care professionals rarely or never diagnose ME/CFS, and this could lead to potential disease misclassification.
[...]
Cultural reasons may also explain this finding of misclassification [26]. A study of cultural differences that may be involved in the non-recognition of ME/CFS as a debilitating disease with high socio-economic impact in Europe would be highly desirable [9,33].

A sensible recommendation given the above?

Firstly, research is best conducted by screening the community, instead of via primary care physicians, because this would help to minimise both selection and referral biases observed in clinical samples [26,27]. This screening may be done by means of the DePaul Symptom Questionnaire (DSQ) [44] or the United Kingdom ME/CFS Biobank Participant Questionnaire (UKMEBPQ) [45].

The UK GWAS study intends to screen prospective participants directly (no referral) using CureME's questionnaire, right?

But a very, very bad bit for epidemiology purposes is saying that the CDC-1994 criteria can be used on their own. Unlike the previous paper from the socio-economics working group*, the recommendation of using multiple diagnostic criteria out of CDC-1994, CCC and IOM is only "additional":

Fourthly, to confirm ME/CFS cases, the CDC−1994 [1], Canadian Consensus Criteria [21], or Institute of Medicine criteria [3] criteria are found acceptable by EUROMENE. Additionally, the use of several independent case definitions is advisable because this may provide a more comprehensive picture of the epidemiology of ME/CFS in Europe and enhance comparability between studies.
[...]
ME/CFS cases are best identified by at least one of the following three case definitions: the CDC−1994 [1], Canadian Consensus Criteria [21], or Institute of Medicine criteria [3].

* The Development of a Consistent Europe-Wide Approach to Investigating the Economic Impact of Myalgic Encephalomyelitis (ME/CFS): A Report from the European Network on ME/CFS (EUROMENE). https://www.mdpi.com/2227-9032/8/2/88/htm

 

[Andy]

The UK GWAS study intends to screen prospective participants directly (no referral) using CureME's questionnaire, right?

Almost. Potential participants will be required to confirm that they have had an official diagnosis of ME (or CFS, CFS/ME, ME/CFS) recorded in their medical records, and then they will be screened by CureME's questionnaire. Given the numbers that we need to recruit, we certainly won't, and can't, be relying solely on medical professionals referring their patients on to the study.

 

[Ravn]

The long and the short of this review is that nobody's been interested enough in us to even figure out how many of us there might be (in Europe). No surprises there. Sigh.

One of the three - three! - studies that made it into the review was done in Iceland in 2001 so didn't include any of the more recent criteria for the simple reason they didn't exist yet. But usefully the study did try to compare prevalence according to 4 different criteria in use at the time, with results ranging from 0 to 4.9% (Holmes and Lloyd criteria respectively).

It is notable that many of the CFS respondents worked full time and put their illness down to stress or overwork - hmm....

Strangely, the authors appear to make a difference between CFS and Iceland Disease which I thought was considered an early ME outbreak? But they don't explain any further, just make that weird comment about phobia levels being the same in CFS and Iceland Disease.

That this study still figures amongst the three most relevant prevalence studies in Europe today really says it all.

A general question about statistics:

They say: "As the population of Iceland totals about 280000 inhabitants, a random sample size of 4000 was deemed to be quite sufficient."

Is that a valid approach when you're looking for something you expect to be quite rare? In this case they would have expected results potentially as low as 1/1000, so 4000 questionnaires sent out - 63% of which were completed - seems low? In the event they didn't find anybody at all fitting the Holmes criteria.

Th e stud y was carried ou t to estimate th e prevalence of chronic fatigue syndrome (CFS) inIceland. No previous prevalence studies known to us hav e bee n undertaken in Iceland or inScandinavia. A 95-item custom-made questionnaire was sen t to 400 0 randomly selected peo -ple. The response rate wa s 63% . The questionnaire was constructed to include questions onal l the item s foun d in th e fou r mos t common criteria for diagnosing CFS; th e criteria bein gAustralian, British an d American. Results sho w ver y different prevalences according to thecriteria used . The prevalence ranged fro m 0 to 4.9%, with th e mos t established criteriayielding a prevalence of 1.4%. Re-test validity of the questionnaire was good, th e followingresults ar e based on the selection criteria by Fukuda et al. (Fukuda K, Straus SE, Hickie I,Sharpe MC, Dobbins JG , Komaroff A, et al. The chronic fatigue syndrome: a comprehen-sive approach to it s de Ž nitio n an d study. An n In t Med 1994;121:953–9). Women were in amajority (78%); thei r mea n age was 44 , the y wer e full y employed and worked lon g hours.The y believed tha t th e onse t of thei r symptoms wa s stres s related. The typ e of wor k wasunskilled in the majority of cases. A signi Ž cant proportion of the males felt a constantbuzzing in thei r ear s (PB0.05). Foo d suppliants were use d daily by signi Ž cantly mor ewomen tha n me n (PB0.01). Men had mor e frequently phobic symptoms (PB0.001)thandid women. Differences wer e foun d in the prevalence of phobia and pani c (PB0.001)between women in the CFS grou p compared to healthy ones . A positive correlation wasfoun d in th e prevalence of phobia between women in th e CFS group an d thos e with IcelandDisease.

Sorry about the weird copy & paste effect.
Líndal, E., Stefánsson, J. G., & Bergmann, S. (2002). The prevalence of chronic fatigue syndrome in Iceland - A national comparison by gender drawing on four different criteria. Nordic Journal of Psychiatry, 56(4), 273–277. doi:10.1080/08039480260242769
sci-hub.se/10.1080/08039480260242769

 

[Milo]

If they don’t count you, you don’t exist, no problem, right?

 

[cassava7]

@Sly Saint In this thread: https://www.s4me.info/threads/me-ac...tition-is-preparing-a-resolution-on-me.13569/