FHIR Data Standards Wales for PSOM v1.0.0-rc1
Important: This is the release candidate of the FHIR Data Standards Wales for PSOM version 1.0 Implementation Guide. It is intended for trial use, and is published for early comment and feedback. Click here to give feedback.

Profiling Guidelines

Profiling strategy

Profiles can serve various purposes, such as:

  • Documentation;
  • Validation;
  • Exchange/implementation.

The degree of restrictions applied to a profile depend on the purpose of the profile. It could be helpful for implementers to have more restricted profiles as guidance (i.e. documentation and validation). On the other hand, there is a strong desire to have solutions that can be re-used across multiple use cases (i.e. exchange/implementation).

The profiles for NHS Wales PSOM are based on the underlying conceptual model and will serve both a documentation and validation purpose. Therefore, the common principle for these profiles is:

  • Only constrain elements that are used in the mapping.

The Task and Questionnaire profiles are heavily influenced by the SDC Implementation Guide.

This results in profiles that:

  • Have mappings to elements in the data set;
  • Have constrained target profiles relevant in the mapping;
  • Have additional specifications for an unambiguous exchange.

Mappings

All PSOM Metadata elements have been mapped to dedicated elements in use-case specific profiles such as CarePlan and Task. For further details regarding their specific locations and additional information, please refer to the PSOM FHIR Data Model of this Implementation Guide. Each of the profiles SHALL have a traceable relationship with the Metadata elements. ElementDefinition.mapping: is a free text mapping "inside" the profile. We use the mapping elements in profiles to map the Item Reference and the Name of a Metadata element to resource elements.

On the root element of the StructureDefinition, the mapping should thus be defined as:

<mapping>
    <identity value="PROMs-Metadata-d2-2a" />
    <name value="NHS Wales DSCN Metadata Mapping" />
</mapping>

A specific element can then be mapped using:

    <element id="CarePlan.identifier">
        <path value="CarePlan.identifier" />
        <mapping>
            <identity value="PROMs-Metadata-d2-2a" />
            <map value="MPRPX004X" />
            <comment value="Referral ID"/>
        </mapping>
    </element>

In addition to the mappings, the .short of the element SHALL also contain the Name of the Metadata element.

Slicing

Slicing is applied to .identifier to specify Health Board specific information i.e., referralID. This slicing approach conforms to the profiling strategy applied for DataStandardsWales profiles.

Examples

Examples are developed to reflect the DataStandardsWales-PSOM profiles. The examples are minimal and only represent the PSOM metadata elements or required FHIR elements. Where applicable, the created examples are derived from the original DataStandardsWales examples. Metadata mappings are represented in the examples as comments in xml, containing the Item Reference and the Name of the Metadata element.

    <!-- MPRPX004X Referral ID -->
    <identifier>
        <system value="https://fhir.cavuhb.nhs.wales/Id/referral-identifier" />
        <value value="12345678" />
    </identifier>

Questionnaires

Questionnaires are generated from the DSCNs/LPDSs as-is whenever possible. The following elements of a Questionnaire are determined by the corresponding information in the DSCN:

Questionnaire element DSCN column name
.version PROMs Tool / Character Code
.item.linkId Question Reference
.item.text Question Text
.item.type with .item.answerValueSet if Value Set is specified; choice
.item.type if Value Set / Example is Free text; string
.item.type if Value Set / Example is Score/Scale; integer or decimal
.item.answerValueSet Value Set

The Data Item Name (also referred to as Field Name) is not represented as a Questionnaire element directly. However, this column is used to name the corresponding CodeSystem and ValueSet. When the Value Set / Example column specifies that there is no return value, this part of the DSCN is not specified in the Questionnaire either, as this Questionnaire is not filled in by Patients.

Because a Questionnaire is not directly filled in by users, this gives the following implications:

  • No rendering is generated, nor any user interface options.
  • .item.required, .item.enableWhen, .item.readOnly, and .item.initial are not defined.

Questionnaire terminology

CodeSystems and ValueSets of Questionnaires are created to show what the answers of a question within a DSCN are. All codes from the CodeSystem are represented in the ValueSet as well, instead of including the complete CodeSystem. This is decided for readability purposes.

Versioning and Releases

This project uses package-level versioning as the primary mechanism for versioning FHIR artifacts. This means that the artifacts within a package are not individually versioned, and should be considered a consistent set. Package versioning is based on Semantic Versioning. Labels ‘-alpha’ and ‘-beta’ are used to indicate whether a package release is a prerelease. Alpha indicates a prerelease that is likely to change in a breaking way. Beta indicates a prerelease that is feature complete and ready for extensive testing. Version updates to conformance resources typically do not affect their canonical URL.

Publication management

PSOM FHIR artefacts are versioned and released using FHIR NPM packages. When a new package version is released, release notes must be included. In addition to the package, a new version of the Implementation Guide is also published. This ensures that all stakeholders are aware of any changes and can implement the new version of the package correctly.