Jim

Case

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Jim Case

None noted.

Jim Case 

Nicola Ingram 

A Briefing Note has been written to inform the community of practice about changes to the dose form modeling to include the use of newly published concentrate dose forms (added as required by the EDQM mapping project) in the modeling of clinical drugs in the International Edition of SNOMED CT. The intent is to gather feedback on a change to Editorial Guidance for clinical drug concepts with dose form of drops or spray (feedback to be received by 22th April).

The document is attached to the meeting agenda above.

DIscussion:

The briefing note was presented and we have requested input on the  proposal by April 22, 2023 

Jim

Case 

At the 2023-02-27 EAG conference call, the EAG approved the inactivation of the Navigational concept hierarchy. The EAG members requested a Briefing Note for the Community of Practice outlining the rationale and steps for inactivation.  The briefing note is attached for review.

Update 4/4/2023:

In discussions with the UK, it was discovered that the current use of Navigational concepts are the result of maps from Read version 2 to SNOMED provided to primary care vendors.  The erroneous nature of the maps may be a result of the movement of concepts from their original location in the taxonomy to the Navigational concept hierarchy at variable times in the past.  Examples:

Concept                                                                                                               Original hierarchy               Moved to Navigation hierarchy

160237006              History/symptoms (navigational concept)                            Context-dependent category            2006-01-31                    

309157004              Normal laboratory finding (navigational concept)               Findings                                             2009-07-31

267368005              Endocrine, nutritional, metabolic and immunity disorders   Disorders                                           2003-01-31                     

243800003              Test categorized by action status (navigational concept)     Context-dependent category            2010-01-31                    

250541005              Biochemical finding (navigational concept)                         Findings                                             2009-07-31

The UK will provide SNOMED International with a list of mappings to navigational concepts and their current use cases.  SNOMED will provide replacement concepts for these prior to inactivation of the navigational concept.  Briefing note will be revised to reflect this new information.

Discussion:

Review of the proposed inactivation based on the new information from the UK.

Decision:  SI will update the briefing note to reflect the new information and distribute it to the EAG, CMAG and Clinical leads groups.

•  Jim Case to update the BN and distribute to EAG, CMAG and Clinical Leads

Jim Case 

Based on input from Monique van Berkum (document attached to agenda above) and the Gravity project, 13 "at risk" concepts submitted by the Gravity project were inactivated.  Additionally, a recommendation to create the necessary pre-coordinated concepts for use in the HAS REALIZATION relationship for the At risk model has mitigated the current need to extend the range of HAS INTERPRETATION, for the purposes of modeling risk findings as well as eliminated the need for a DUE TO relationship that resulted in inconsistent modeling patterns.

This remodeling has been performed and should be available in the May 2023 release.

The full model currently being used for "At risk" concepts is defined in the template located at: At [qualifier] risk of [finding/event] (finding) - Ready for review

•  Jim Case to continue modeling based on revised editorial guidance.

Document by James R. Campbell  related to risk calculators is attached to the agenda.  

The primary premise is that the "proper use of HAS_INTERPRETATION when INTERPRETATION has value of an Observable entity is that the valueset must adhere rigorously to datatype restrictions specified by the SCALE_TYPE defining the Observable concept."   Additionally, the following extensions to the concept model are proposed:

1) Expand the valueset constraints for 719722006|Has realization (attribute)|

Note: Range for this attribute is currently << 272379006 |Event (event)| OR << 404684003 |Clinical finding (finding)| OR << 71388002 |Procedure (procedure)| OR << 719982003 |Process (qualifier value)|

2) Add a Risk property to <<118598001|Property (qualifier value)|
3) Create a role hierarchy for 363713009|Has interpretation (attribute)| to support additional attributes including concrete domains and ordered refsets that are needed
for Quantitative and Ordinal or quantitative Scale types
4) Aligning with the editorial principles of LOINC, a policy for employing refsets defining the valuesets for observable entity concepts with scale type of Nominal, Ordinal and
Ordinal or quantitative. These refsets would allow interpretation of evaluation findings and conceivably could by integrated into classification.

In reference to content development in the International release, the following must be considered:

• On 2020-04-29 the EAG approved an editorial policy: When defining observable entities for the international release, the SCALE TYPE attribute will not be used. If extensions would like to add specific subtypes of observable entities that include the SCALE TYPE, they are free to do so.
  When using observable entities to define clinical findings, international concepts that do not include a SCALE TYPE relationship would be used a values for the INTERPRETS relationship. The exception to this guidance are existing "vital sign" observable entities that have been defined with the SCALE TYPE of "Quantitative".
• The majority of Observable entities in the International release of SNOMED CT are not modeled, so Scale Type is not available.
• There are currently no International concepts that require concrete values for HAS INTERPRETATION
• It is not possible to support both concept based values and concrete values in the same range for a scale type such as "Quantitative or Ordinal"

Discussion:

James R. Campbell described the use of risk calculators at UNMC.  One question that had arisen was the editorial decision to not include a value for the SCALE attribute to Observable entities in the international release.  This was due to the fact that the "expected" scale was adequately described by the PROPERTY attribute value, and the TECHNIQUE attribute value as well as the observation that many of these risk calculators allowed for either a Ordinal or quantitative value.

However, the Regenstrief/SNOMED agreement obviates much of this as the LOINC extension will necessarily contain SCALE TYPE as that is a required LOINC part in the definition of a LOINC term. 

A discussion ensued on the need to create clinical findings that represented the combined observable-value that is represented by the INTERPRETS/HAS INTERPRETATION relationship group.  This did not seem to be the way that the data are collected in the EHR.  However, it was recognized that there is a need for clinical findings to be used as members of a value set bound to an observable to support assessments. 

Decision:

The discussion ended with consensus that there is no compelling use case at this time to expand the range of HAS INTERPRETATION at this time. The need to revise the editorial policy related to the inclusion of SCALE TYPE in modeling observable entities in the International release will be re-evaluated by the SNOMED content team.

Should "Mechanical complication of device" be a disorder or a finding?

Current situation:

111746009 |Mechanical complication of device (disorder)| has 215 subtypes, all of which refer to a failure of a device without specifying a deleterious effect on the patient. 

       e.g. 285961000119107 |Mechanical breakdown of prosthetic heart valve (disorder)|

We also have disorder concepts that refer to a patient condition due to mechanical failure of a device 

       e.g. 5053004 |Cardiac insufficiency due to prosthesis (disorder)|

Without specifying the resultant condition associated with device mechanical issues, is it appropriate that these are represented as patient disorders, or should they be findings that may be related to disorders in the patient?

A briefing note using "Leakage of device as an example is located here.

Discussion:

Without an associated condition in the patient it is unclear whether there is an adverse impact on the patient.  In general, if the device is implanted, it can be assumed that there is a negative impact. These should be retained as disorders.  Each of the subtypes would need to be evaluated as to the potential impact on the patient.

2023-04-04

Additional issues and questions:

1. If we agree that implantable device malfunctions result in an adverse condition in the patient, should the FSN reflect that, e.g. "Disorder due to mechanical breakdown of prosthetic heart valve"? Consensus - no...
2. SNOMED CT does not have a general classification of implantable devices.  Is the following definition suitable to provide editorial guidance? FDA - "Medical implants are devices or tissues that are placed inside or on the surface of the body." Consensus - no

Definition provided by John Snyder - "Medically implanted devices refer to any manufactured device, prosthesis, or biological construct that is surgically implanted into or physically attached to the body to aid in the diagnosis, treatment, or monitoring of a medical condition".

Discussion:

Implantable devices might be considered as a type of body part, thus a disorder of the device would of necessity cause a problem in the patient and should be a disorder. While there may not be a morphological abnormality, there is an abnormality of the device. Is a new attribute needed to represent device abnormality?  This discussion is restricted to medical devices and not transplanted tissues and organs.

Some implantable devices are not prostheses.

With reference to a proposed definition, what does physically attached mean?  Look at how FHIR has addressed this.  Should imply some introduction method, rather than just an attachment to the body.

The top level concept could be moved to clinical findings.  There is an issue with the term "complication".  Subtypes would be individually reassessed.  Propose that the disorder boundary start with mechanical complication of implanted device.

Kin Wah will provide documents related to a discussion on implantable devices.

Update 2023-04-10:

Upon investigation, as expected, these concepts (i.e. Mechanical complication) are classification derived (ICD-9, ICD-10, and ICD-11) and refer to injury or harm to a patient caused by a failure, breakdown, or malfunction of a device.  Coding guidance indicated that (for ICD-11) the disorder caused by the mechanical complication should be coded first and then associated with the device. Thus, the intended meaning of these concepts imply a disorder in the patient due to some issue with the device. The actual terms are index terms in the ICD.  Example:

PK91.22 Cardiovascular devices associated with injury or harm, mechanical or bioprosthetic valves (ICD-11)

    Index term: Mechanical complication of heart valve prosthesis

This would suggest that these concepts are correctly placed in the taxonomy, and they are currently mapped to ICD disorders (i.e. injury or harm to patient) but are possibly not modeled sufficiently to express the implied meaning.  A new approach to modeling these concepts will be undertaken to clean up this sub-hierarchy.

Definition of device malfunction from the US Code of Federal Regulations TITLE 21--FOOD AND DRUGS, CHAPTER I--FOOD AND DRUG ADMINISTRATION, SUBCHAPTER H - MEDICAL DEVICES
PART 803 -- MEDICAL DEVICE REPORTING: "Malfunction means the failure of a device to meet its performance specifications or otherwise perform as intended. Performance specifications include all claims made in the labeling for the device. The intended performance of a device refers to the intended use for which the device is labeled or marketed..."

Jim Case 

Penny Livesay 

Review of Glossary definition for "Sufficiently defined concept".  See sufficiently defined concept

Additional information on Necessary and sufficient conditions: D.2 Necessary and Sufficient - Examples

Can a concept be sufficiently defined if part of the meaning of the FSN is captured only in the wording of a stated primitive parent, not in defining attribute-value relationships? For example: Joint laxity (finding) is primitive since it has no defining relationship(s) that capture the "laxity" aspect of the FSN meaning.  Many of its subtypes (e.g. Elbow joint laxity (finding), Hand joint laxity (finding) etc.) are modeled as sufficiently defined based on the stated parent Joint laxity plus the finding site relationship specifying the joint involved? 

Inconsistency between the Editorial Guide and the SNOMED Glossary:

Current Editorial guide states "A concept is sufficiently defined if its defining characteristics are adequate to define it relative to its immediate supertypes".  It is not clear whether "defining characteristics" here refers to defining attribute-value relationships specifically or to the logical definition as a whole.

• Does "relative to its immediate supertypes" imply only the defining relationships and not information based on the FSN of the primitive parent? 
  • Would this mean then that all subtypes of an intermediate primitive concept must also remain primitive?
• If information represented in the FSN of a stated primitive parent can be considered to fill a gap in meaning left by the defining attribute relationships, this policy should be clearly stated (and ideally illustrated with an example) in the editorial guide and under Intermediate Primitive Concept Modeling

The SNOMED Glossary states: ""A sufficiently defined concept has at least one sufficient definition that distinguishes it from any concepts or expressions that are neither equivalent to, nor subtypes of, the defined concept".

• Is "definition status" of a concept part of the definition of a concept? Currently it acts in that way.  This occurs when two or more concepts have the same defining relationships, but only one is marked as sufficient defined.  Those that are not marked as sufficiently defined classify as subtypes.
  • In some cases the SNOMED concept model is inadequate to "fully" define the meaning of an FSN, yet can provide a sufficient definition to make it unique within the terminology.  In these cases the primitive subtypes with the same relationship have the necessary relationships, but not sufficient definitions.

The Glossary also states "Prior to July 2018, SNOMED CT could only support one sufficient definition for each concept could not represent the 8801005 | Secondary diabetes mellitus (disorder)| example above(Note: this example is no longer valid and needs updating in the glossary). A further limitation, that also prevented formal representation of that example was the stated relationship file was only able to represent necessary conditions.". 

• Proposed clarification: "Prior to July 2018, SNOMED CT could only support one sufficient definition for each concept, and the stated relationships comprising that definition could represent only necessary conditions. A concept such as 417163006 |Traumatic or non-traumatic injury (disorder)| , which can be caused either by a traumatic event or by an intrinsic disorder (such as a tumor), could not be sufficiently defined within these constraints, since neither | Associated morphology| = | 37782003 |Damage (morphologic abnormality)| nor| Due to| = 773760007 |Traumatic event (event)| is necessarily true. Assigning the concept two sufficient definitions can, however, allow the full meaning of 417163006 |Traumatic or non-traumatic injury (disorder)|  to be formally represented. (See sufficient definition)."

Lastly, there is a statement: "Following these changes a concept will only be marked as sufficiently defined if it is sufficiently defined by relationships. However, the OWL axioms may provide a sufficient definition that cannot be fully represented as relationships."

• This has come about with the ability to model concepts with multiple sufficient axioms using GCIs. Proposed clarification: "Following these changes a concept will only be given a definition status of Defined if it is sufficiently defined by the stated relationships in a single axiom. However, multiple OWL axioms may provide a sufficient definition representing different sufficient but not necessary relationships. These concepts will retain the default status Primitive but function as sufficiently defined concepts that will subsume subtypes."

Discussion:

Concepts with identical definitions aside from the Definition status may be classified as supertype/subtypes, due to the limitations of the concept model to allow for more robust definitions. This is being left with the EAG for additional comments to be reviewed at the April meeting. There is a question about whether the browser can be modified to show an icon that can identify a concept as having GCIs.  A question will be forwarded to the tech team.

Update 2023-03-26:  The current SNOMED Browser displays concepts with GCIs  in the stated diagram view; e.g.:

•  Jim Case to send a note to the MAG inquiring about the value of a new definition status that identifies a concept with GCIs

Next meeting April 4. SNOMED business meeting