The Prevalence of Pediatric Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in a Community-Based Sample (2020) Jason et al.

Thanks for the usual smart analysis.

1. Good point about people who know someone with fatigue being more likely to take part in the study. For accuracy, 43,000 people answered the phone and 20,000 were excluded as had no kids or were a business. Of the remaining eligible 23,000, 5600 took part (24%). So there is scope for selection bias as a result of people knowing that it was a fatigue study, but not as much scope as your starting figure of 148,000 suggests. And I am not sure how this compares with previous studies.

2. Interesting point about a 83% having PEM — I will ask about that.

3. I think this is probably the best adolescent prevalence study out there. It uses a community sample which, despite the bias, is likely much better than trying to go through physicians , through instance, where you depend on physicians spotting it. And it involves a medical evaluation, including a physical exam, which was carried out by Dr Ben Katz, one of the top Paediatric consultant specialising in ME/CFS in the US. It also included a psychological screen and fatigue questionnaire.

4. Although I am also surprised about the very low rate of previous diagnosis, I don't have any reason to doubt it. See above for how diagnosis was carried out. Also, previous studies (one by Jason, won by the CDC also found extremely high rates of non-diagnosis in prevalence studies). Don't forget this is the US where access to medical care is patchy at best. And they have a big problem with physicians being willing to take the illness seriously.


I plan to blog about it is next week, once I've had the chance to harvest the wisdom from this thread .

 

Thanks to the many people who helped answer my question but I still find it puzzling.

I can understand that if you have relatively mild ME/CFS and can still try to live a normal life (like going to school or work) that many people carry on without an answer for their symptoms. But if 95% were undiagnosed, this must have been the case for patients who more severely ill as well. So this cannot be the full answer.

Other have pointed out to me the difficult situation of healthcare in the US: people who lack financial resources might not be able to see a lot of doctors. But the majority of households with young ME/CFS in this study wasn't exactly poor. The study says: "For the youth identified with ME/CFS, 50% had family incomes of $100,000 or greater, and 71% of parents had a college or higher education." 31% of the families had an income of 150.000 or more. So most households were educated and had some financial resources to see doctors.

So I don't think that explains it either and still wonder what the situation of those undiagnosed patients was. Did they have an alternative (but false) diagnosis? Where they still in the process of searching what's wrong? Did most of them had a mild form where they could try to ignore their symptoms and carry on as best as possible? I hope that the Chicago research team will further report on this.

I was thinking: if recognition of paediatric ME/CFS is really that poor so that 95% doesn't receive a diagnosis, it could be that quite a few patients reived an incorrect diagnosis (sleep disorder, lupus, Addison, hypothyroidism, haemochromatosis etc.) that might have been wrongly considered as an exclusionary condition. After seeing many doctors who couldn't find out what was wrong, some might have given such a tentative diagnosis based on small abnormalities in lab tests so that the patient received some kind of answer. So what I'm trying to say is that there could be ME/CFS patients with such an incorrect diagnosis in the exclusionary group who never proceed to clinical examination, which could lead to underestimation of the prevalence rate. Just a thought...

 

I suspect an important reason for young people going undiagnosed is that they seek help but are given harmful advice, most likely in the form of a diagnosis of depression or some psychological explanation for school refusal. Or they're just repeatedly told that everything is fine when it's clearly not. They then lose faith and stop seeking help.

It's hard enough for us adults to disagree with doctors and challenge incorrect narratives. Children don't stand a chance.

 

It is also fairly easy for children to be quite sedentary- whether it is intended or unintended. So the behaviors of underperforming at school, becoming couch bound, having vague symptoms but feeling ok enough to go to school, all can be camouflaged, to a degree. And then teens, they really like to sleep till early afternoon...

So parents may be confused as of what is going on. Hormones? Typical teen? Looks exhausted but maybe it was what he/she did at school?

 

I googled "causes of school refusal" and checked Wikipedia. These bring up long lists of various causes, all of them psychosocial or psychiatric. The possibility of other illness is not seriously considered. Presumably it is assumed that illness is rare and generally handled well by doctors.

There is also the suggestion that school refusal frequently involves "complaining of physical symptoms".

It could therefore be difficult to distinguish absence from school due to an undiagnosed illness that produces physical symptoms from other forms.

 

Yeah I might have been a bit harsh, although many of the 93,989 households that never answered their phones and did not return multiple voicemails might have heard the message on voicemail and decided to ignore it - something people who know young persons with significant fatigue might not do. There might also be sources of selection bias if the 100.000 households that could not be reached differ in some way from the 40.000 that were reached.

I think previous prevalence studies were able to reach a higher percentage of their target population. I wonder if this is a general trend; that the lack of landlines is making it much harder to do community-based studies in multiple areas of science. When I first read the prevalence studies in depth a couple of years ago, the first thing that I thought was that researchers won't be able to do this again because you can no longer reach people as easily. I wonder if there are other methods like contacting people through their internet provider or by a random list of cell phone numbers (although this probably results in privacy issues).

Yes, I think I agree.

I don't know how others think of this but given the many uncertainties, I tend to interpret prevalence studies as only giving a rough indication, like saying that it's probably somewhere between 0.1% and 1% rather than between 0.01-0.1% or 1-10%.

I didn't mean to raise doubts about the accuracy of it, I just expect that there must be another mechanism/explanation behind than the ones usually given (patients didn't have access to doctors due to financial reasons or they had a mild form and just carried on). I would like to know if they had been given an alternative diagnosis or were still in the process of going from doctor to doctor to figure out what's wrong and did the patients/parents suspect it might be ME/CFS; had they ever heard of it? Feels like there's an explanation missing, hope the authors will give more info about this in future publications.

 

This is a bit off-thread but I recently received an SMS from the Norwegian Institute of Public Health asking if I have chronic afflictions after having been bitten by a tick. On the website they say that according to statistic calculations they had to send this SMS to 270 000 random Norwegians in order to get representative results.

Perhaps SMS is better than landlines for such screenings?

 

The CDC increases participation in their surveys by sending out multiple letters first, given they're a government department (yes, even in America, many people trust government departments!), it might work better for them than for private/academic researchers.

 

When I read about children with ME they are all very sick and I wonder about the ones like me.

I was 14 and never missed a day of school until my last year, I worked in Woolworth's on a Saturday, went out Saturday night, walked for miles as I couldn't afford transport, not to mention scrubbing floors and cleaning at home as well as gardening - no, honestly I had ME.

I took an enteroviral infection and was never the same. I may have felt tired, but I was continually told how exhausted adults were all the time so I thought everyone felt worse than me and just got on with it. I had no temperature regulation, my eyesight would go, my speech would go, my mind would go blank and my writing become illegible. I also had severe pain in my back and legs and joints.

Worse of all was my bladder shutting down completely for hours. I also had the fatiguability I have today where everything stops for a few seconds or so then I can carry on.

I was taken to the doctor and given a lot of tests eventually being told I had migraine with more of the funny symptoms and less of the headaches. I actually did have migraines but the funny symptoms were all ME.

Looking back PEM could account for a lot of the episodes and everything got worse over the years.

I never complained of fatigue so would not have been given a diagnosis of CFS - I've never had fatigue that lets me do 50% less. Even now pain and other things stop me before fatigue does, so if doctors are looking for fatigue and school absences then someone like me would not be diagnosed.

(I did finally experience profound fatigue but it turned out it was diabetes so it is not the case that I just don't recognise it)

 

The onset of ME for many pediatric patients includes not just the physical but the serious cognitive symptoms as well. Those cannot be explained away as "teenage sleep patterns", "exercise avoidance".... When a 12 year old abruptly cannot do the mental math they could do effortlessly at age 5, when they try hard but cannot learn new material, when they cannot follow even written directions AND they suddenly have no stamina (when days before they could go on "forever") there is something seriously wrong with them. Healthcare professionals who are dismissive of this to the parent or the patient cause serious harm.
The same is true for someone with a gradual onset though it is not as easy to discern.
In general I don't see enough about the impact of cognitive exertion and cognitive symptoms in discussions about ME --- but I know that it is not as much of an issue for some as it is for others.

 

Thanks for your post Michiel. A really helpful start to the discussion.

Yes, me too – even having read the responses from others.

Quite. Just to emphasise this point: if 25% of cases are severe, then this would mean that at least 80% of severe cases (20/25) were undiagnosed, and probably much more than that. If the paediatric rate is as high as 0.75%, then I wonder if the percentage of severe cases (however they are defined) may be substantially lower than 25%. I’ve only skimmed the paper but I didn’t see anything about how many could be classified as severe. Is there any data in the paper from which this could be calculated?

Yes. I’d also be very interested to know to outcomes of those diagnosed with ME/CFS in this study – how many recover, improve, stay the same, deteriorate over different time frames.

Do we know if there there is any intention to do any follow up studies? Did the participants give consent to be contacted for follow-ups?

In my view, to ”suspect that it might be ME/CFS” would also translate in many people’s minds as “fear that they might have to put up with an ME/CFS diagnosis and accept that nobody knows what is causing the symptoms or how to treat them.”

To me, ME/CFS doesn’t tell us very much about what is wrong – it just tells us that a person’s responses to questions about their symptoms are consistent with a specified criteria and there is no other known explanation for those symptoms. I know that others feel differently, but for me it has always been an unsatisfactory diagnosis – one that I still struggle accept after 27 years of severe illness. I tried very hard not to be given it, and I still hope that it may be replaced with something else one day.

I know that many people have had to fight very hard for a diagnosis of ME, and that many people have benefited significantly from being diagnosed. But I also think we should be aware that there may be many people who would be resistant to being diagnosed, or having their children diagnosed, for both valid and invalid reasons. Perhaps this is one factor in the reported high rate of under-diagnosis.


With regard to whether the respondents were representative of the population as a whole, I think this bit from the discussion is important:

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To me this looks like a useful study but it also raises several unanswered questions. I’m not someone who subscribes to the idea of “real ME”. There are just people who meet different diagnostic criteria, some of which are more useful than others. However, I would be very surprised if anything like 0.75% of children have got what I’ve got.

One thing this study emphasises to me is how important it is to find reliable biomarkers so that we can accurately differentiate between patients with different conditions for which there may be very different prognoses, and for which different treatments may be appropriate.

One of the positives of finding a high prevalence rate is that a higher disease burden should equate to greater investment in research. A potential negative is that if the diagnosis is being made too loosely, then there is the risk that research may not focus on those who have the greatest needs, who may have different pathologies.

Thinking about the reported high prevalence rate, something I have often wondered is whether researchers or physicians asking leading questions may result in false positive diagnoses. This would be impossible to study in ME without biomarkers, but I would have thought it would be possible with chronic conditions which have reliable diagnostic biomarkers. Undiagnosed referrals to, say, an endocrinologist could be randomised in advance of a standard consultation. Some could be asked to describe their symptoms without being asked any leading questions, and others with. After the standard consultation and relevant tests the relative reliability of asking leading questions could be determined with respect to objective diagnoses. I’m just thinking aloud really, but does anyone know if anything like this has ever been studied?

Finally, I note that the ratio of females with ME/CFS in the Jason et al study was 25/42 = 59.5% which is lower than some estimates.

Looking forward to @Simon M ’s blog, as ever.

 

I totally agree @Denise.
When a youngster cannot remember how to do the A-level Maths that she had known inside out a couple of months earlier and her tutor says "If I was meeting her now I would recommend doing BTechs not A-level Maths", there is clearly something seriously wrong.

However I know of at least one person with ME who was able to do a Maths degree, but had more pain than my daughter who fortunately does not often have pain???

 

Regarding the prevalence of severity.

Consider that the patients with characteristics that make it easier to be diagnosed are likely to be overrepresented in especially non-random sample but also random sample studies.

I believe that a sudden onset, greater illness severity, documented or obvious infectious onset are some of these characteristics. I think this tells us that the undiagnosed portion of patients would tend to be on the lower end of severity and with more gradual onset (where one can deny or ignore the problem for a while). As our ability to diagnose the illness increases, we might uncover that it's more prevalent than we thought. Unfortunately our ability to diagnose it is still rather poor I think.

This could also mean that our mental model of how ME/CFS looks like could be biased towards the more easily diagnosable patients.

This is one of the reasons why I've become uncomfortable with narrow case definitions. It's true that there is a risk, and historical problems of excessively broad definitions used in research but in clinical practice, I think there probably is an enormous problem of underdiagnosis that has not only hurt the undiagnosed but also our efforts to advance research. Every undiagnosed person is one less person able to participate in studies, donate to research, participate in advocacy.

We might also discover in the future that it's more common in men than we thought.

 

A good thing about Leonard Jason is he doesn't “waste” lots of data. We’ll probably see 5-20 (?) more papers on this study.

 

This is probably what one is looking for in many ME/CFS studies assessing fatigue. Lots of people in society can have a vague feeling of fatigue but one is looking for something that affects function.

 

It's possible people who are more severely affected some or all of the time could have been missed due to the necessity to go to a hospital.

 

So more people could have had symptoms such as the post-exertional malaise symptoms, but at a lower level of severity or frequency.
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So the prevalence would have been higher, looking at the other 2 criteria. Leonard Jason is interested in the sort of issues so I expect a breakdown of the data may be published in future papers.