Changes to digital terminologies

To support other enhancements, end users will need access to dm+d historic codes to ensure medications that have had more than one code change can still be correctly found. 

To avoid affecting existing products and process flows, the dm+d historic codes will be added as an added XML release file with the dm+d weekly release and into the Terminology Server.

What to consider

• If your system supplier manages your dm+d data, ask them if and how they plan to use this data
• If the trust manages dm+d data, will you start to use this data? 
• Which dm+d concepts do you use that contain fields for ‘current’ and ‘previous IDs’

The dm+d historic code file will be a bonus/supplementary file within the weekly TRUD release.

Historic code data files will be found in the ZIP file under a folder named: HISTORIC_CODES

XML filename format: f_history1_0DDMMYY.xml

XSD filename: history_V1_0.xsd

dm+d virtual therapeutic moietys (VTMs) and virtual medicinal products (VMPs), where an equivalent exists, use SNOMED CT International Edition (IE) concept identifiers as their unique ID. Recent changes to the IE model and editorial policy mean that the IE definition of VTM and the dm+d definition no longer align. 

In dm+d, the VTM groups together VMPs that have only that VTM - for example, paracetamol and codeine VMPs are not children of paracetamol VTM.

The IE definition of these existing concepts (that dm+d is linked to) has changed to ‘contains some’. That is, the VMPs below a VTM have this VTM and possibly others too, whilst concurrently introducing new ‘contains only’ concepts. Therefore, some dm+d VTMs are now linked to incorrect IE concepts.

This will have implications on implementations using VTM/VMP inheritance and links to support - for example, allergy.

All VTMs using IE codes will be changed to the correct ‘contains only’ VTM where applicable. Where a new IE ‘contains only’ VTM does not exist, a UK extension ID will be assigned.

What to consider

• Do you use/map to VTM concepts?
• If your system supplier manages your dm+d data, ask them how they plan to make these changes in their systems and what impact there may be to end users
• How will dm+d updates be managed where you have systems that integrate with each other?
• If the trust manages dm+d data, what will be the process for taking and handling the code changes in dm+d updates? Do you use ‘current’ and ‘previous’ VTM IDs?

The availability of dm+d ‘historic codes’ will support you with these changes.

dm+d VTMs and VMPs (where an equivalent exists) use SNOMED CT International Edition (IE) concept identifiers as their unique ID. Recent changes to the SNOMED CT IE model and editorial policy mean that the IE definition of VMP and the dm+d definition no longer align. This change in the IE led to a requirement to update the concept ID for several hundred high volume (usage) VMPs in dm+d. The impact was destabilising for EPS and has led to mistrust in the stability of the dm+d product long term.

To shield EPS from further ‘unplanned for’ changes, because of IE churn, it is proposed to move all VMPs to extension ID and no longer use IE concept identifiers. This would mean a one off, managed, implementation of change but would mean protection (of dm+d) from any further instability created by international change.

The link to the SNOMED CT IE would be at VTM level as content at this level is stable, hence minimal risk of churn despite keeping international identifiers.

In dm+d, ingredients are authored for VMPs but not currently for VTMs. VTM-Ingredient link information cannot be derived from any content currently in dm+d. A VTM can, at times, have an ingredient that is a level of abstraction above the VMP ingredient - for example, base vs salt.

Ingredients will be added for VTMs at time of authoring as it will aid in the modelling/classification of the SNOMED CT UK Drug Extension content.

The SNOMED CT UK Drug Extension has a ‘6th box’ – the Trade Family (and a link to an associated Trade Family Group that groups together trade names that have, for example, different active ingredients), a brand equivalent to a VTM. This extra data is not available in the native dm+d XML release.

Trade Family and Trade Family Group will be added to the dm+d authoring process and extra XML files produced for this information to be distributed with the native dm+d XML release. This will streamline the process for implementers with a need for Trade Family and Trade Family Groups but who only use dm+d (and not the SNOMED CT UK Drug Extension).

In dm+d, ingredients are authored for VMPs but not currently for VTMs. VTM-Ingredient link information cannot be derived from any content currently in dm+d. A VTM can, at times, have an ingredient that is a level of abstraction above the VMP ingredient - for example, base vs salt.

Ingredients will be added for VTMs at time of authoring as it will aid in the modelling/classification of the SNOMED CT UK Drug Extension content.

dm+d uses SNOMED CT substances as the ‘ingredients’ assigned in the dm+d model. These substances in dm+d are currently a flat file with no associations/links between them.

NHS England will define a correct hierarchy for substances within the SNOMED CT UK Drug Extension to enable correct classification of drug extension content (allowing better QA and automated build) and to support implementors in their use of ingredient content.

This will become increasingly important on the implementation of Identification of Medicinal Products (IDMP) standards and alignment to it for interaction with MHRA data and use in the International Patient Summary.

dm+d uses SNOMED CT forms and units of measure in the dm+d model. These are currently flat files in dm+d with no associations/links inherent in each file.

NHS England will define a correct hierarchy for form and unit of measure within the SNOMED CT UK Drug Extension to enable correct classification of drug extension content (allowing better QA and automated build) and to support implementors in their use of form and unit of measure content.

This will become increasingly important on the implementation of Identification of Medicinal Products (IDMP) standards and alignment to it for interaction with MHRA data and use in the International Patient Summary.

NHS England is making a number of changes to align the SNOMED CT UK Drug Extension modelling to reflect the SNOMED International model for national drug extensions, where it is deemed to fit UK requirements. This work is being done in order for the NHS to use functionality available in the RF2 format, that was not previously available in RF1, which restricted how certain aspects of the UK Drug Extension could be implemented. 

This work will also enable the NHS to use the power of our authoring tools, enhance our quality assurance processes and work towards international standardisation.