The purpose of the Substance Hierarchy redesign project is to eliminate errors and improve the consistency and usability of the substance hierarchy by reducing the overloaded subtype relationships and adding new attributes to capture this information correctly. The parts of the strategy involve:
This project has been previously stalled due to resource shortages, in addition it was decided that further planning needed to be done with regards to how to approach Substances before executing any changes. The Substance plan has been completed however some points below may not have been in the execution scope.
|1.||SOW completion based on the provision of a part-time resource from HSCIC.||1. Provide a detailed work plan for the update of substance representation.||1.Completed March 20 2017|
SOW work - Draft -Substance Project Draft Outline
While past work on the project has focused on the pharmaceutical substances used in drug modelling, this phase of the redesign project includes all the substances and the multiple sub-hierarchies, including the drug and medicament substances, allergens, toxins and dietary substances.
Draft Deliverables which may be revised or eliminated
The ‘allergen class’ hierarchy is causing a number of quality issues for a number of reasons. Firstly, the relationships between allergen concepts and other substance concepts in the hierarchy are causing a number of incorrect inferences through inheritance. Secondly, the hierarchy is incomplete, further reducing the usefulness of the hierarchy. While there are over 7000 concepts in the “Drug and medicament” substance hierarchy, only half of these are covered by ‘Drug allergen’ (4700).
2. Increasing the comprehensiveness of the model -document requirements and propose progression plan.
Past meetings and project groups have often raised the issue of the lack of relationships between certain substance concepts and the need to identify links between other concepts. For example, some substances which act prodrugs or metabolic precursors to other substances currently have no link, even though they may be closely related clinically. Another large issue that has been raised by the project group is the requirement for a relationship between the salts and the bases of a substance.
3. Identification and Removal of non-defining characteristics-document requirements and propose progression plan.
There are a number of concepts that describe substances based on non-defining extrinsic characteristics, for example, therapeutic roles. The inclusion of these results in many substances being incorrectly organised. The therapeutic purpose is something intrinsic to a product, and often associated with a specific dose or form.
4. Editorial Guidance/Rules-document requirements and propose progression plan.
There are currently few editorial guidelines which define the consistent naming conventions for substances in SNOMED CT, particularly in the grouper concepts in the hierarchy. Guidelines are also required to help determine when a grouper should be created and when a grouper definition is required. It is expected that this will be an ongoing process as required work throughout the whole redesign project.
5. Structure of the Overall Hierarchy/Systemic inspection-document requirements and propose progression plan.
As there is a large number and variety of sub hierarchies and content, the whole hierarchy would benefit from a manual inspection by members of the content team with knowledge of chemical, physiologic, therapeutic, preparation and manufacturing aspects of chemicals and devices, as well as a fundamental understanding of the principles of sound ontological design and description logics.
1. Completed Jul 2018
2. Completed Jul 2018
3. Completed Jul 2018
4. Completed Jul 2018
5. Completed Jul 2018
4. Changes in the substance hierarchy as the result of Allergy project requirements:
5. Updated Editorial Guidelines where required.
Completed for Jan 2019