Predictors of Persistent Medically Unexplained Physical Symptoms: Findings From a General Population Study, 2018, Van Eck Van Der Sluijs et al

https://www.frontiersin.org/articles/10.3389/fpsyt.2018.00613/full

Highlighted in this post by @Roy S ,https://s4me.info/threads/me-cfs-an...r-geraghty-et-al-2018.4707/page-5#post-123442

Keith Geraghty says this about the study in a tweet.
https://twitter.com/user/status/1064893432773120000

 

I don't have the mental endurance to read the full paper, so I hope it's all right if I ask question & mention points related to the abstract and stuff connected to it that may be answered in the study...


1. They say they selected subjects who participated at follow-up. How does one account for cohort bias in such a case (maybe those who were unavailable for reassessment shared some important commonality that would change conclusions if one had the opportunity to look at the entire dataset)?

2. How would one know which symptoms are complications of having a chronic medical disorder in some people over time and which ones are correctly (according to however that is defined anyway) attributed to MUS?

3. Not having a paid job, lower education, female sex, parental psychopathology and chronic illness should all be related to being poorer than average. The Netherlands are said to have one of the better healthcare systems out there, although I do not actually know if this is true. I'd be pretty interested to see if any correlations here are also correlated to austerity measures that have been taken in the last decades in health care and social security since this should make being poor a bigger factor in health! It might also predispose the dataset in a very obvious way since if less medical tests are done which would have helped diagnose problems, the incidence of 'MUS' should obviously rise - although this makes the assumption that this term is defined in a way in which I would colloquially interpret it.

 

from 2009
"One in six NHS patients 'misdiagnosed'
While in most cases the misdiagnosis did not result in the patient suffering serious harm, a sizeable number of the millions of NHS patients were likely to suffer significant health problems as a result, according to figures. It was said that the number of misdiagnoses was “just the tip of the iceberg”, with many people still reluctant to report mistakes by their doctors."

 

oops did that before as well, thanks for reminding me!

 

The persistant symptoms were (1) Intestinal symptoms (2) Back pain or (3) "other" (open question). The overall "persistancy rate" of around one third is interesting. But studies like this, which are still ultimately retrospective cohort studies - even if those candidates are selected as part of a population based study, are subject to response/questionnaire answering biases.

The study is badly presented as some of the data, eg subgroup analysis based on the above groups was not done.
No data visualisations were provided.

Secondly, the finding of (higher levels of) physical functioning predicting MUS is curious and we really need to see some data visualisations to get a clue as to what was going on.

The authors simply provided the OR given two models model 1 included: "logistic regression analyses adjusted for sex and age", model 2: all significant variables adjusted for sex and age from model 1 were entered simultaneously in one more fully adjusted logistic regression analysis, to find unconfounded estimates of risk factors for persistency".

 

The study reports "In the adult general population, MUS were persistent in over one third of the subjects with MUS at baseline. Persistency was significantly predicted by parental psychopathology, number of comorbid chronic medical disorders, and physical functioning." (Sorry, I too could not face looking the article at present.)

If the study had been looking at the persistence of any condition including those with a recognised biomedical aetiology would they have found the same results. It strikes me that they are not looking specifically at what they call 'MUS' rather they are looking at generally recognised factors associated with ill health.

 

un fortunately cannot remember where I read this nugget of information but up to 33% of diagnoses where found to be wrong I think this was widely reported a year or so ago .

 

“Bad things come in threes”

In other news, fire is often hot.