Classification Derived Concept

The guidance recommends that EQUIVALENT_TO associations be between

194733006 |Mitral and aortic stenosis (disorder)| and  
79619009 |Mitral valve stenosis (disorder)|
 60573004 |Aortic valve stenosis (disorder)|

This is wrong. These three concepts are not equivalent.

A referenced component should not have more than one active “EQUIVALENT_TO  " at any given time. If it's equivalent to two things, those two things are surely equivalent too?
There's also have consequences for "data healing" activities on longitudinal data stores so the cardinality of these associations is important.

Also, I get that there are some classification concepts that use “and” when they possibly mean “or”, but I’m not convinced this is an example of. Is the intention to get rid of all the conjunction concepts? That seems overzealous as many are very valid, and used. For example, do you prevent people from recording “Diarrhea and vomiting”. It’s easy to say Information models should handle this, but that’s not a simple implementation exercise without causing a poor user experience.

Groupers like “Menopausal and postmenopausal disorders (disorder)" I agree are not appropriate. But I don’t think a blanket rejection of “co-occurrence/conjunction” is the right move.

Similarly for “without”. Although we can’t (currently) model negation, Negative assertions are just as important as conjunctions. “Placenta praevia without haemorrhage" “Refractory migraine without aura".

We obviously don’t want to precoordinate every combination but many are useful, and removing existing concepts is not without downstream impact.

Hi Matt Cordell,

A number of issues here, I'll try and respond to each in turn.

ICD has made our lives more difficult by occasionally using "and" when they mean "and/or". In this specific instance, we have interpreted 194733006 |Mitral and aortic stenosis (disorder)| to mean true conjunction i.e. the patient has both mitral AND aortic stenosis. I believe that this is how the average clinician would interpret this concept if they came across it in the patient's notes.

Based on this interpretation, if we were to inactivate 194733006 |Mitral and aortic stenosis (disorder)| it would be clinically unsafe for us not to provide BOTH 79619009 |Mitral valve stenosis (disorder)| and  60573004 |Aortic valve stenosis (disorder)| as necessary replacements and insist that BOTH are represented within the patient's active record.

If the interpretation of the "and" was that it actually represented "and/or" then 194733006 |Mitral and aortic stenosis (disorder)| would be considered to be ambiguous as we would not know whether it represented mitral or aortic or mitral and aortic stenosis. In this instance, we would use POSSIBLY_EQUIVALENT_TO for each possible interpretation and the user should choose ONE concept that represented the meaning at the time the record was made.

We are not suggesting that all instances of a true "and" should be inactivated and a number of our editorial policies provide for exceptions for all the reasons that you have highlighted. However, as a general principle, we believe that there is a strong case for recording each disorder that a patient suffers separately as each will likely require separate and different clinical management.

If you feel that “EQUIVALENT_TO" does not adequately portray the meaning we have ascribed to it, we would be happy to consider suggestions for an alternative word/phrase.

Hi Former user (Deleted) 

Hope you don't mind a classification comment:

• The concept contains "Not elsewhere Specified"

 Just noting that "Not elsewhere Specified" is not in the ICD classification or SNOMED CT (active or inactive).

Prior to their inactivation the ICD-10 '.8' codes existed as 'other specified' concepts in SNOMED CT (majority inactivated as part of bulk Limited inactivations (WAS_A)_ when  .8 and .9 NOS codes were both inactivated in the NHS circa 2005 but not separately identified as 'other specified' which I think this is now proposing in the form of a drop-down list).  There are no 'other specified' concepts remaining in the current SNOMED CT but 3331 inactive 'other specified' concepts that may be impacted by inactivation of their active historical association targets.

"Not elsewhere classified"  checked the ICD-10 instruction manual it says that: The words ‘not elsewhere classified’, when used in a three-character category title, serve as a warning that certain specified variants of the listed conditions may appear in other parts of the classification. For example:
J16 Pneumonia due to other infectious organisms, not elsewhere classified.

Also NEC is used in the ICD-10 index to direct the user if they cannot locate that particular condition, usually pointing to the .8 or 'other specified' codes to use as the residual, or bucket codes when the condition cannot be classified elsewhere. None exist in the current SNOMED but about 400 inactive 'elsewhere classified' concepts.

• Not Otherwise Specified 

Whereas the .8 or 'other specified' codes match your description of "enabling the recording of conditions that exist but are not currently specifically identified within the current version of the classification in use" (see my comments regarding NEC above) the NOS codes are the .9 codes in ICD. The ICD-10 instruction manual has this explanation: "The letters NOS are an abbreviation for ‘not otherwise specified’, implying ‘unspecified’ or ‘unqualified’."

Sorry for being a geeky clinical coder 

Nicki