How to capture a Patient's healthcare literacy in FHIR?

Objective

For a specific use case we need to capture a Patient's healthcare proficiency. For that we have three classifications, eg literate, informed, and curious.

Question

What is the FHIR conformant way (resource, extension, etc) to store this?

Context

• We capture the patient's healthcare proficiency via Questionnaire and QuestionnaireResponse.
• With a Subscription to QuestionnaireResponse we trigger the post processing in the backend.
• Our backed is tasked to turn the QuestionnaireResponse into a FHIR conformant structure.
• We make use of StructureMap to define the mapping from QuestionnaireResponse to target FHIR resources.

Hence which target resource or other FHIR conformant way to store this data?

There is not a specific element in the Patient resource to store 'literacy in healthcare'.

I assume you want to keep this information inside the Patient resource rather than a related resource.

I would propose at least two different conformant ways:

• Use a string extension
• Use a metadata tag

Here are the examples:

string extension

{
  "resourceType": "Patient",
  "id": "123456",
  "extension": [
    {
      "url": "http://example.org/fhir/StructureDefinition/literacy",
      "valueString": "informed"
    }
  ],
  "name": [
    {
      "use": "official",
      "family": "Doe",
      "given": [
        "John"
      ]
    }
  ],
  "gender": "male",
  "birthDate": "1980-01-01"
}

metadata tag

{
  "resourceType": "Patient",
  "id": "123456",
  "meta": {
    "tag": [
      {
        "system": "http://example.org/fhir/CodeSystem/literacy",
        "code": "informed"
      }
    ]
  },
  "name": [
    {
      "use": "official",
      "family": "Doe",
      "given": [
        "John"
      ]
    }
  ],
  "gender": "male",
  "birthDate": "1980-01-01"
}