The 12th Invest in ME Conference, Part 1
OverTheHills presents the first article in a series of three about the recent 12th Invest In ME international Conference (IIMEC12) in London.
Discuss the article on the Forums.

Comorbidities in the diseasome are more apparent than real: What Bayesian filtering etc

Discussion in 'Latest ME/CFS Research' started by Dolphin, Aug 2, 2017.

  1. Dolphin

    Dolphin Senior Member

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    For what it is worth:

    Free full text:
    http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005487

    CFS gets a mention.
     
  2. Dolphin

    Dolphin Senior Member

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  3. Learner1

    Learner1 Professional Patient

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    Er...they seem to be a bit shy on comorbidities for CFS...

    How about these, which seem to be very common on this site and which my expert CFS doctor made a point of testing for?

    Hashimotos
    Celiac disease
    MCAS
    Herpes family viruses

    I'm sure others here can add to this list.

    These types of analyses remind me of the saying "garbage in, garbage out."
     
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  4. SamanthaJ

    SamanthaJ Senior Member

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    Since when has migraine been categorized as a somatic disorder? Or am I misunderstanding the use of the word 'somatic' here? (I know there's another meaning for it, just a bit hazy on what that is)
     
    Last edited: Aug 2, 2017
  5. Esther12

    Esther12 Senior Member

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    Roughly: 'Somatic' means bodily, 'psychosomatic' means bodily symptoms related to mental processes.
     
  6. Luther Blissett

    Luther Blissett

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    soma = greek word for 'body' (i.e. not mind)

    somataform = denoting physical symptoms that cannot be attributed to organic disease and appear to be psychogenic.

    I get confused around these words too :)
     
  7. Jonathan Edwards

    Jonathan Edwards "Gibberish"

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    From what I can see they are meaning somatoform or psychosomatic. Arthritis comes up as NOS (not otherwise specified) which is a bit of a joke. I get a whiff of GIGO here.
     
  8. Esther12

    Esther12 Senior Member

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    We've finally gone full circle with their word games.
     
  9. CFS_for_19_years

    CFS_for_19_years Hoarder of biscuits

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    Thanks for posting the abstract.
    Posted for the reading-impaired (including myself) who can't read a wall of text.
     
  10. Karen Kirke

    Karen Kirke

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    Here’s a bit more detail on what they say about CFS specifically (I have divided the text into smaller chunks and added bolding):

    “Another interesting cluster of comorbid disorders are irritable bowel syndrome (IBS), fibromyalgia (FM), chronic fatigue syndrome (CFS) and migraine; all of them showed strong link with depression based on the text-mining data (S1 Dataset). The BDMM showed that they are strongly co=morbid with depression in the full analysis but when the onset is before depression these strong relationships were absent. (S5 Fig).

    The high posteriors in the full analysis, and their sharp decrease in the restricted analysis may indicate that these disorders are heterogeneous themselves: in some subgroups of disorder the symptoms are part of the depression phenotype with high biological overlap but other subgroups maybe independent of depression or adversities that non-specifically predispose to depression.

    Similar patterns emerged for insomnia, gastro-oesophageal reflux (gord) / gastric reflux, prolapsed disc/slipped disc, and gastritis/gastric erosions suggesting that in some circumstances they are directly related to depression but in others they are independent of depression (see web tool, Co=MorNet:bioinformatics.mit.bme.hu/UKBNetworks).

    When we changed the depression definition to the one defined by low mood and anhedonia, ignoring somatic symptoms [46], only chronic fatigue and fibromyalgia showed co=morbidity with depression, especially with severe depression, suggesting that IBS, migraine, and other above mentioned somatic disorders may have specific relevance for depression dominated by somatic symptoms (for further detail see S3 and S4 Figs and S1 Appendix).”



    And another excerpt, where they discuss the implications of the above findings:

    “Multimorbidity pattern of IBS, FM, CFS and migraine with depression
    “Migraine [34], IBS [68], FM [69], and CFS [70] are highly comorbid with depression based on epidemiologic studies. It is therefore puzzling that they involve different etiological mechanisms. In addition, their symptoms often overlap making it difficult to apply diagnostic categories.

    We found that these disorders were not relevant when they occurred before depression but were highly co=morbid in the full analysis. The probable explanation is that in general, these disorders are related to consequences of depression and only specific subtypes of these disorders can be expected to have causal relations, e.g. shared biological background with depression.

    For example, a genetic risk score analysis demonstrated that migraine with comorbid depression was more genetically related to depression than to pure migraine, which suggests that migraine might develop as a consequence of different polygenic backgrounds [71]. Similarly, a large general population cohort study confirmed that FM, CFS and IBS increase the odds of depression and anxiety but that most patients who suffer from FM, CFS and IBS have no mood or anxiety disorder [72].”


    http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005487#pcbi.1005487.s006
     
  11. Londinium

    Londinium Senior Member

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  12. SamanthaJ

    SamanthaJ Senior Member

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    Thank you @Esther12 and @Luther Blissett . I think I used to know that. I've been reading too much BPS stuff :ill: They've forgotten what 'somatic' means too.
     
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  13. Karen Kirke

    Karen Kirke

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    I would have been interested to see how autoimmune conditions would have patterned here.

    @Jonathan Edwards, I’d be interested in your interpretation of the quotes from the paper in my post above (some repeated below)?

    I think this means that there is no real relationship between CFS and depression for people who, at the onset of their CFS, have never been depressed – have I understood that correctly?

    It makes a lot of sense to me that a subset of the people who are currently being diagnosed with CFS (or in the case of this study, self-reporting as having CFS) may, in fact, have a condition that overlaps biologically with depression, but that other subgroups have no biological overlap with depression. Treating all subsets the same would lead to ineffective treatments, and potential harm, for the subgroups whose pathophysiologies are not targeted by the treatment.

    I find the wording of this bit ambiguous. I am not sure if they are saying that CFS is a consequence of depression (i.e. depression causes CFS) or that depression is a consequence of CFS (i.e. CFS causes depression). While I have come across anecdotes of people who self-report CFS and state that it started with depression, and Naviaux et al (2016 - the dauer paper) were keen to point out that people seemed to end up at the same dysfunctional metabolism regardless of what the trigger for their CFS was, I’d be concerned that we could also be drifting into territory here where chronic fatigue is being confused for CFS. I hope it's awkward wording that could be interpreted to mean the opposite of what they mean, and that what they actually mean is that some people get CFS, and then, afterwards, as a consequence of their CFS, get depression.
     
  14. A.B.

    A.B. Senior Member

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    Depression is probably way overdiagnosed.
     
  15. Snow Leopard

    Snow Leopard Hibernating

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    The methodology also comprises a meta analysis of the papers that have been included in the study.
    The observed associations also reflect the biases of the design of the studies themselves, eg studies that bothered to measure comorbidities and the types of comorbidities, rather than any underlying association.

    I think they are overreaching when trying to imply causality given they have not considered the biases associated with diagnosis of depression and CFS - eg patients more likely to get a depression diagnosis before CFS due to doctor ignorance, and patients with a CFS diagnosis first, are very reluctant to get a depression diagnosis afterwards, unless they have severe depression.
     
    Last edited: Aug 2, 2017
  16. Sean

    Sean Senior Member

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    As with deconditioning, I think the most interesting aspect of ME patients' mental health profile is that it isn't much worse considering the circumstances we have to try to survive in.
     
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  17. Valentijn

    Valentijn WE ARE KINA

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    SF36 shows normal mental health for ME patients. So I doubt the studies included are using depression questionnaires which focus on actually feeling depressed, rather than merely being less active.
     
  18. Jenny TipsforME

    Jenny TipsforME Senior Member

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    Another factor is that many of us are misdiagnosed as having depression on the diagnostic journey to a ME diagnosis. I don't know how this would be represented.
     
  19. Woolie

    Woolie Gone now, hope to see you all again soon somewhere

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    I think the main problem is that the maps assume that the constructs being measured have some integrity. That they are measuring coherent and non-overlapping things.

    If you're depressed because you're ill, this will show up as a link between your illness and depression. Since depression is such a nonspecific measure of distress/physical symptoms - and probably doesn't refer to any single phenomenon - it is likely to be linked with all sorts of other things that cause distress and physical symptoms generally.

    Depression is also confounded with social class. So sometimes depression may be indexing bad life situations more generally. And if those bad life situations are also associated with other diagnoses, then that will show up as an association too.

    "somatic" is one of those words that looks neutral but is always used to imply psychosomatic.
     
  20. Woolie

    Woolie Gone now, hope to see you all again soon somewhere

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    They say:
    They used a self-report measure of depression, that looks at things like sadness/loss of joy, negative thoughts about self or future and nonspecific physical complaints like sleep problems, fatigue, poor concentration.

    Now see how their statement looks when you substitute the actual thing they did measure whenever you see the word "depression":
    Doesn't sound all that astounding now, does it?
     

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