Anemia (disorder) - v1.0

Bruce Goldberg With the supertype here, shouldn't it be 414022008 |Disorder of cellular component of blood (disorder)|?

Cathy Richardson . Actually, I had meant to delete this template. At the very least this needs more discussion. I based this on the model of anemia that is currently in SNOMED which defines anemia as both a low hemoglobin and an erythropenia. This is in contrast to all of the definitions I can find online which indicate anemia is a low hemoglobin or an erythropenia

e.g WHO definition: 

Anaemia is a condition in which the number of red blood cells or the haemoglobin concentration within them is lower than normal.

I will leave this template up but changed the description to on hold - pending further discussion during an author's call. I believe this topic has been discussed in the past.

Jim Case Bruce Goldberg - I would like to pick this up again as it has appeared as an issue driven by ICD-11 content. I have discussed with Dave Robinson and he is interested in assisting me with this revision. Any objections? thanks, Monica

Monica Harry ,

No objection from me.  Do we have a way of representing a GCI in a template?  I assume that is what is required here.

I have no objections either if GCIs are indeed allowed in templates. If so, that would help in creating more templates representing disjunctive states. I eagerly await feedback from Peter and Yong.

Yongsheng Gao Peter G. Williams - See previous discussions. Is there a way to represent GCIs in a template?

Thanks both and yes Peter, I was thinking along the same lines of the optional RG. Will review as Yong suggests and def. discuss on Wed. 

The problem with either using GCIs or optional RGs for interpretations of low hemoglobin or erythropenia is that subtypes of anemia would need to be defined as either having either low hemoglobin, low RBCs or both. In most cases of anemia both indices are affected but sometimes only one measurement may be reduced e.g. mild hypochromic anemias not have a low hematocrit and in thalassemia with extreme microcytosis in which the RBC count may be increased. It would be very difficult imo to assign one or more appropriate RGs to the 514 descendants of anemia. I had brought this up during a Tuesday authors call and we agreed at that time that anemia could not be sufficiently defined.

A possible solution however is based on the “rigorous” definition of anemia from UpToDate below. If we create an observable entity of red cell mass, we could define all anemias with a single role group of interprets red cell mass +has interpretation below reference range.

Anemia — Anemia can be rigorously defined as a reduced absolute number of circulating red blood cells (ie, a reduced red blood cell mass as determined via blood volume studies). However, blood volume studies are not practical for this purpose, cost-effective, or generally available. As a result, anemia has been defined as a reduction in one or more of the major red blood cell (RBC) measurements obtained as a part of the complete blood count (CBC): hemoglobin concentration, hematocrit (HCT), or RBC count. In practice, however, a low hemoglobin concentration or a low hematocrit is most widely employed for this purpose.

I have added a few comments as this work overlaps with the work I am currently doing on 118245000 |Measurement finding (finding)| in which all of the anaemias currently reside as a consequence of using the INTERPRETS/HAS INTERPRETATION role group.

I have a number of questions, of which the answers would help me model more consistently the content of 118245000 |Measurement finding (finding)| concepts and may have a bearing on the work planned for the anaemias.

There are a number of potential duplicates as determined by their modelling in this hierarchy e.g.

62574001 |Erythropenia (finding)|

165423001 |Red blood cell count low (finding)|

Erythropenia is defined as:

"the presence of decreased numbers of erythrocytes in the blood, as occurs in some forms of anaemia. Also called: erythrocytopenia" -  Steadman's medical dictionary

Interestingly UpToDate returns no matches on a search for 'erythropenia' and PubMed only 67 many of which relate to animal studies.

We have said that findings represent a 'point in time' state and so the interpretation of measurement findings should probably be restricted to an interpretation of the single observation and not an ongoing state.

So my questions are:

1. Is 'erythropenia' a true synonym of 'low red blood cell count'? - I think this may be unclear, but if it were agreed to be a duplicate it would resolve all of the remaining queries.
2. Should we have a means of representing the ongoing state, as represented by a number of repeated measurements of low red blood cell counts in the same way as we have 45007003 |Low blood pressure (disorder)| and 12763006 |Finding of decreased blood pressure (finding)| and would 'erythropenia' modelled as a disorder be a way of achieving that? - recognising the many discussions we have had regarding findings v disorders
3. Should we be using a role group that specifies a point in time measurement to represent an ongoing state, given that it is the ongoing state which often/usually determines the presence of a disorder?
4. If we wish to retain 62574001 |Erythropenia (finding)| as representing the ongoing state, retained as a finding how would we model the concept to show that it was an ongoing state rather than a point in time interpretation of an observable?

Opting for the simple solution would be my preference

Discussed with Bruce Goldbergand he will raise this at the next QI call for resolution.

The GCI axioms represent the disjunctive meaning for either lower haemoglobin, low RBC, or both. It is different from multiple role groups in an axiom. This is also different from multiple axioms. I created a simple Apple ontology to demonstrate the differences in model and classification results. 'Sweet or red apple', as a disjunctive concept, is modeled by two GCIs. You might also notice some interesting side effects of using multiple axioms.

After looking into a bit more detail of subconcepts of anemia, the GCIs are not necessary for classifying these subconcepts. Most of these subconcepts are belong to association patterns. Please note these GCI axioms are not included in the inferred relationship file. So, they won't facilitate queries based on attributes/values. Given the above the discussion, I think treating anemia as a primitive concept, similar to diabetes, would be okay to model those subconcepts. Let's discuss at the QI call.

 GCI and multiple axioms.owl

Jim Case , Yongsheng Gao  As an example of a concept which is currently classified under anemia but does not contain "anemia" in the FSN there is 19442009 |Heterozygous thalassemia (disorder)|. It is modeled as shown with:

363713009 |Has interpretation (attribute)| = 281300000 |Below reference range (qualifier value)|,
              363714003 |Interprets (attribute)| = 14089001 |Red blood cell count (procedure)| }

which would classify this concept under anemia. In truth however the RBC count may be increased in Heterozygous thalassemia (Thalassemia minor). A GCI would still classify this under anemia if the the total hemoglobin is low. The MCH is low in the Thalassemias but I need to ascertain whether total hemoglobin is also low.

Thalassemia minor is characterized by reduced MCV and MCH, with increased Hb A² level [29].

Galanello R, Origa R. Beta-thalassemia. Orphanet J Rare Dis. 2010;5:11. Published 2010 May 21. doi:10.1186/1750-1172-5-11

Hi Bruce Goldberg, because anemia has been incorrectly defined by two role groups, all subconcepts of anemia have inherited lower RBC and lower hemoglobin. We cannot rely on the inferred model of subconcepts of anemia. Therefore, each model of its subconcepts has to be reviewed and remodeled. 

"Two separate and partially overlapping types of anemia: hypochromic anemias, resulting from a decreased amount of hemoglobin in red blood cells, and hemolytic anemias, resulting from increased red blood cell destruction". "The combination of hypochromia and increased hemolysis defines a distinct subset of entities, of which thalassemias are the most common". Atlas of Diagnostic Hematology Copyright © 2021 by Elsevier, Inc. All rights reserved. https://www.clinicalkey.com#!/content/book/3-s2.0-B9780323567381000038?scrollTo=%23hl0001043

The concept  40108008 |Thalassemia (disorder)| can be model by low hemoglobin as a necessary condition. Then, it will be classified under the GCI anemia.  The due to relationship also needs to be modelled in order to be classified under 14514008 |Anemia due to disturbance of hemoglobin synthesis (disorder)|

Thalassemia is anemia of varying severity due to inadequate production of globin chains
Thalassemia is a quantitative hemoglobin disease; hemoglobin is normal but an insufficient amount is produced

Thalassemia
Elsevier Point of Care (see details)
Updated May 7, 2019. Copyright Elsevier BV. All rights reserved.

https://www.clinicalkey.com/#!/content/clinical_overview/67-s2.0-bed2df48-2c67-43b5-b2b6-40e4e2a22571

More detail about the classification of thalassemia can be found in the above two references as well. 

Bruce Goldberg,

At this point, since 14514008 |Anemia due to disturbance of hemoglobin synthesis (disorder)| is primitive (as are all of its subtypes), could we not just use that as the parent for Thalassemia until such  time as we can decide whether this term is needed or can be defined? It would still classify under Anemia.  It would not conform to this template, and we could create a new one to support these concepts.

Yongsheng Gao,

Thanks for updating this for the GCI, but I am wondering what the need for all of the attributes are in the top axiom as all of the relationships are optional. Could the top level axiom just be a subtype axiom for Disease? Also, you have the subtype axiom as 0..1 as well.  Is that intentional?

I agree and will create a new template at the end of this week.

Remodelled Anemia as per template. 

<< 414022008 |Disorder of cellular component of blood (disorder)|: {363713009|Has interpretation (attribute)| = 281300000|Below reference range (qualifier value)| and 363714003 |Interprets (attribute)| = 441689006 |Measurement of total hemoglobin concentration (procedure)|} {363713009|Has interpretation (attribute)| = 281300000|Below reference range (qualifier value)| and 14089001 |Red blood cell count (procedure)|}

Filter by term = Anemia 
and "State" with definition type = All
The 'State' will exclude those concepts inferred two RGs from |Anemia|. Those 'Inferred' should have already lost 2 RGs after the model change to |Anemia|.

A simple example, 413532003 |Anemia due to blood loss (disorder)| can be remodelled as fully defined by:  |Anemia| is the PPP parent.  
IS A = |Anemia| and |Due to| = |Bleeding|
This type of concepts does not need to have two GCI axioms.