Introduction

 Background

SNOMED CT terminology provides a common language that enables a consistent way of indexing, storing, retrieving, and aggregating clinical data across specialties and sites of care.

SNOMED International maintains the SNOMED CT technical design, the content architecture, the SNOMED CT content (includes the concepts table, the descriptions table, the relationships table, a history table, and ICD mappings), and related technical documentation.

Purpose

This document provides a summarized description of the content changes included in the January 2019 release of SNOMED Clinical Terms^® (SCT) International Release.

It also includes technical notes detailing the known issues which have been identified and agreed to be released. These are content or technical issues where the root cause is understood, and the fix has been discussed and agreed, but has yet to be implemented.

The SNOMED International Release Notes are available alongside the January 2019 International Edition release.

Scope

This document is written for the purpose described above and is not intended to provide details of the technical specifications for SNOMED CT or encompass every change made during the release.

Audience

The audience includes National Release Centers, WHO-FIC release centers, vendors of electronic health records, terminology developers and managers who wish to have an understanding of changes that have been incorporated into the January 2019 International Edition release.

Content Development Activity

Summary

Continuous quality improvement and enhancement of existing content is an ongoing process by SNOMED International for every release. The January 2019 International Release has seen a continuation of the work driven by contributions from: Kaiser Permanente Convergent Medical Terminology (CMT), Global Medical Device Nomenclature Agency (GMDNA), Orphanet and other domain specific collaborations as well as requests received via the Content Request System (CRS). Additionally quality improvement activities are in progress for new and enhanced content through project driven initiatives which are also summarized below.  Also included as work items for every release are various updates to SNOMED CT derived maps such as ICD-10 and ICD-O and details are also included in these release notes.  Information about editorial decisions may be found in the SNOMED CT Editorial Guide, mapping guidance for ICD-10 can be found at this link https://confluence.ihtsdotools.org/display/DOCICD10.

Content Quality Improvement

Anatomy 

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  • Descriptions of 44 concepts updated to conform to the editorial guidance for the naming convention for laterality. 

  • The attribute 123005000 |Part of (attribute)| has been inactivated and a new attribute |Proper part of| has been added in the January 2019 release. All part of relationships are inactivated and the different part of relationships will be implemented after the revision of hierarchical relationships for anatomy content. 

  • Revision of hierarchical relationships for anatomy content: the project plan is to review the hierarchical relationships for anatomy content in the production against the inferred relationships from the new anatomy model. The new anatomy concept model has implemented the Description Logic features, e.g. reflective and transitive property, general concept axioms, for consistent logical modeling and inferences. 
    Content review and revision are divided by body systems. There is a total of 12,458 hierarchical relationships in anatomy for review. The revision will improve classification in other hierarchies such as disorders, procedures, observables and situations. In this release, over 4,100 relationships in the musculoskeletal system in body structure and over 6,000 relationships in other hierarchies were reviewed. There are about 2,000 changes to hierarchical relationships in anatomy and concept model for disorders and procedures. Further details can be found at https://snomed.atlassian.net/wiki/display/IAP/Progress+of+IS+A+revision 
    Please note, you may have to register for a Confluence user account in order to access the relevant links above.

  • Revision of nail structures - all 'nail structure' concepts are replaced by nail unit structures to avoid misinterpretation of nail plate structures. |Nail plate structure| is a skin appendage. |Nail unit structure| includes |Nail plate structure| and skin around and under the nail plate. The concept |Nail structure| and its subconcepts were inactivated. Over 60 new nail unit concepts were added. Changes were made to stated relationships for over 300 concepts with impact to inferred relationships for about 500 concepts.

Clinical finding

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    • Fracture 

    • Bacterial infectious disease

    • Disease caused by parasite

    • Sexually transmitted disease

    • Chronic inflammatory disease

    • Aneurysm

    • Arthritis

    • Open wound

    • Closed wound

    • Bite wound

    • Congenital malformation

    • Protozoan infection

    • Closed wound

    • Viral disease

    • Hernia of abdominal cavity - Structural improvement of subtypes of the concept 52515009 |Hernia of abdominal cavity (disorder)|. Further work will be undertaken in a subsequent release on the combined disorders where gangrene and/or obstruction is present due to a hernia as well as incisional hernias.
      
      

    • Burn - Inactivation of burn concepts containing "with loss of body part" and "without loss of body part" approximately 161 concepts.

    • Abrasion - As a result of changes made during the QI project, there are now 2 concepts which have the same preferred term. 
      781488002 |Abrasion of foot (finding)
      211402004 |Abrasion of foot (disorder)
      782201009 |Abrasion (finding)|
      399963005 |Abrasion (disorder)|
      These concepts will be addressed as part the QI project for the July 2019 release.

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    • Stated: A total of 12595 concepts had changes made to the Stated relationships in their models.

    • Inferred: This resulted in 20012 concepts affected by inferred changes.

    • Subsequent review of the Fracture hierarchy of 151 concepts identified no impact upon the previously published maps to ICD-10.

    • Subsequent review of the Burn hierarchy of 375 concepts identified no impact upon the previously published maps to ICD-10.
      
      
      

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    • Hypersensitivity/Allergy/Non-allergic hypersensitivity condition classes defined using General Concept Inclusion (GCI) axioms in order to encompass disorders, dispositions and processes (reactions).

    • Propensity to adverse reaction and Allergic disposition moved from disorders to findings. The concepts were remodeled using the proximal primitive parents with a role group consisting of 719722006 |Has realization (attribute)| with value of allergic process or its subtype. The new convention for descriptions are Hypersensitivity/Allergy/Non-allergic hypersensitivity to X (finding).

    • New Allergic disorder (disorder) hierarchy representing abnormal structures. The allergic disorders are modeled by associated inflammation morphology + allergic process or subtype + finding site X e.g. Allergic rhinitis).

    • The contact hypersensitivity conditions have been remodeled using the new concepts for Immunoglobin E-mediated allergic contact hypersensitivity process (qualifier value) and Non-immunoglobin E-mediated allergic contact hypersensitivity process (qualifier value).

    • New Intolerance to substance (finding) hierarchy created under Propensity to adverse reaction (finding) as a sibling of Hypersensitivity disposition (finding).

    • 414029004 |Disorder of immune function (disorder)| is remodeled and defined by using a pathological process of 769247005 |Abnormal immune process (qualifier value). As a result, it subsumes allergic disorders and allergic reactions.

    • Pseudoallergy condition and Pseudoallergy disposition renamed to Non-allergic hypersensitivity condition (finding) and Non-allergic hypersensitivity disposition (finding) and they have been remodeled following the new concept model.

    • Inactivation of “Allergy to X" concepts where X is a modification of a base substance and replacement with Allergy to the base substance.

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    • 414052000 | Drug allergen by structure |

    • 414057006 | Drug pseudoallergen|

    • 414053005 | Drug allergen or pseudoallergen|

    • 414058001 | Drug pseudoallergen by function|

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    • IHTSDO- 393 Diabetes Complications: The Diabetes Project Group has begun its work on reviewing the current SNOMED CT Diabetes Mellitus disorder concepts. The group is small but is truly international and each member is currently seeking to engage with diabetes specialists within their geographical zone in order to ensure international interoperability within this domain.
      
      

    • IHTSDO-41 Modeling of 'X' in remission - Approximately 170 disorder in remission concepts can now be found in the hierarchy 765205004 | Disorder in remission (disorder) | as well as the hierarchy relating to the underlying disorder.

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    • 371598009 |Heberden's node (finding)| changed to disorder. 201827009 |Heberden's nodes with arthropathy (disorder)| inactivated. 80400009 |External hyperostosis (morphologic abnormality)| moved from under 13814009 |Hypertrophy of bone (morphologic abnormality)| to 4147007 |Mass (morphologic abnormality)| and Heberden node (disorder) remodeled. The result is that Heberden node (disorder) is no longer a subtype of 298745009 |Hypertrophy of upper limb (finding)| but is now a subtype of 416189003 |Exostosis (disorder)|.

    • Intrinsic vs. Extrinsic Asthma - changes made: 

      • 424643009 |Immunoglobulin E-mediated allergic asthma (disorder)| removed synonym "Extrinsic asthma" as semantically non-equivalent and "refers to" 389145006 |Allergic asthma (disorder)|. 

      • 389145006 |Allergic asthma (disorder)| - added preferred term. 

      • "Extrinsic asthma" removed synonyms "Allergic atopic asthma" and "Atopic asthma" and "refers to" 424643009 |Immunoglobulin E-mediated allergic asthma (disorder)|. 

      • 424643009 |Immunoglobulin E-mediated allergic asthma (disorder)| added synonyms "Allergic atopic asthma" and "Atopic asthma".

    • Acquired disorder - Approximately 124 concepts were edited to continue with the work to remove the precoordinated morphology and replace with a single morphology and the occurrence "767023003|Period of life beginning after birth and ending before death (qualifier value)" in the relationship group. 

    • Remodeling of Joint instability - approximately 156 concepts remodeled using approach: FSN: |Instability of X (finding)|, Is a: 404684003|Clinical finding (finding), finding site: X body structure, relationship group: Interprets: 299444001 |Stability of X (observable entity)|/ Has interpretation: 263654008|Abnormal (qualifier value).

    • Additions and improvements in areas of suspected/risk of bullying, abuse, and abandonment in clinical finding hierarchy.

    • Inactivation of 112625008|Cutaneous eruption (morphologic abnormality) in favor of using 1806006|Eruption (morphologic abnormality)| relationship grouped with a finding site, approximately 51 concepts remodeled.

    • Remodeling of joint temperature-related concepts: adding parents, interprets values and sufficiently defining where appropriate.
      
      
      

Convergent Medical Terminologies (CMT)

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      • CMT Ear, Nose and Throat

      • CMT Genitourinary

      • CMT Infectious Disease

      • CMT Injuries

      • CMT Ophthalmology

      • CMT Skin

      • CMT Musculoskeletal

Procedure Hierarchy

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      • Computed tomography 26 new concepts.

      • Magnetic Resonance Imaging 26 new concepts.

      • X-ray 1 new concept.

      • Fluoroscopy 39 new concepts. 

      • Ultrasound 29 new concepts.

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      • Laparoscopic repair of hernia 54 new concepts.

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      • Repair of hernia 48 new concepts.

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    • Improved representation of 305349003 |Admission to department (procedure)| in the area of pediatric specialty and dental clinics by adding additional parents where possible.

    • Relationships were added to, or changed in the procedure (and physical object) hierarchies in the area of spectacles, optical vision aids, telescopes in order to sufficiently define or correct the classification of these concepts.

    • Improved representation of 438579008|Focused ultrasound ablation (procedure)| and descendants.

Collaboration/Harmonization Projects

Event

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      • IHTSDO-1071 - Continued inactivation of transport accidents; movement of all vehicle accidents to children of Transport accidents; Fully-defining some when possible and adding additional parents if appropriate.

Record Artifact

Organism

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      • 268 New concepts (Including 117 Shiga toxin producing E coli concepts) and 12 changes to the existing concepts' descriptions.

      • Inactivation of 21 ambiguous concepts across multiple hierarchies which had included an animal species when referring to an Influenza virus (e.g., Myocarditis caused by avian influenza (disorder), Influenzavirus type A, avian, H5N1 strain (organism)). 6 new concepts were created in this process.

      • Correction of Influenza virus descriptions: Around 350 corrections/changes were made to Influenza virus descriptions over multiple hierarchies (majority in substance hierarchy but also including disorder, procedure and organism hierarchies). Most of the changes consisted of inactivation of the erroneous description and replacement with a new correct description. In addition, two new concepts were added in the organism hierarchy.

      • Application of consistent case sensitivity to organism descriptions containing "Taxon Rank": Change of the case sensitivity setting for 10282 descriptions (over 4964 concepts).

      • Concepts with descriptions that include the word 'unclassified' were inactivated (7 concepts).

      • Duplicate descriptions were identified and corrected for 11 Concepts.

      • Spelling errors were corrected for 29 concepts.

      • Historical associations were corrected for 32 concepts.

Pharmaceutical / biologic product

The following changes will be included in the 2019-January International Release.