MII IG PRO, published by Medizininformatik-Initiative. This guide is not an authorized publication; it is the continuous build for version 2026.2.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/medizininformatik-initiative/kerndatensatzmodul-proms/ and changes regularly. See the Directory of published versions

Terminology Strategies

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Overview of Terminology Approaches

The MII PRO module supports three fundamental approaches for defining answer options in questionnaire items:

1. Inline answerOption: Direct definition of answer options within the Questionnaire
2. answerValueSet: Reference to external ValueSets with flexible composition
3. MII CodeSystems: Full control over the terminology lifecycle

Strategic Decision Criteria

Using Inline answerOption

Available International Standards

Scope: LOINC codes for answer lists with reliable coverage available

Implementation pattern:

* item[=].answerOption[0].valueCoding.system = $LNC
* item[=].answerOption[0].valueCoding.code = #LA6568-5
* item[=].answerOption[0].valueCoding.display = "Not at all"
* item[=].answerOption[0].extension.url = "http://hl7.org/fhir/StructureDefinition/itemWeight"
* item[=].answerOption[0].extension.valueDecimal = 0

Example instruments: PHQ-9, PROMIS questionnaires Advantages:

• International interoperability
• Semantic unambiguity
• Established coding standards

Simple, Static Answer Lists

Scope: Few answer options (maximum 5 options), low likelihood of change, no reuse required

Implementation pattern:

* item[=].answerOption[0].valueCoding.display = "I have no problems in walking about"
* item[=].answerOption[0].valueCoding.code = #1
* item[=].answerOption[1].valueCoding.display = "I have slight problems in walking about"
* item[=].answerOption[1].valueCoding.code = #2

Example instrument: EQ-5D-5L answer scale Advantages:

• Minimal complexity
• Clear implementation
• Low maintenance effort

Extensive Metadata per Answer Option

Scope: Multi-language support, score weights, complex presentation requirements

Example: PHQ-9 with German translations and weighting extensions

Using answerValueSet with MII CodeSystem

Multiple Answer Format Variants

Scope: Identical conceptual answers in different text variants (short form/long form/detailed)

Implementation example: BDI-II

CodeSystem: MII_CS_PRO_BDI_BDI2_AnswerList
* #bdi-bdi2-answer-1a ^property[+].code = #bdi-bdi2-itemWeight
* #bdi-bdi2-answer-1a ^property[=].valueDecimal = 1
* #bdi-bdi2-answer-1b ^property[+].code = #bdi-bdi2-itemWeight
* #bdi-bdi2-answer-1b ^property[=].valueDecimal = 1

ValueSet: MII_VS_PRO_BDI_BDI2_AnswerListShort
* include #bdi-bdi2-answer-0 from system MII_CS_PRO_BDI_BDI2_AnswerList
* include #bdi-bdi2-answer-1 from system MII_CS_PRO_BDI_BDI2_AnswerList

ValueSet: MII_VS_PRO_BDI_BDI2_AnswerListLong
* include #bdi-bdi2-answer-1a from system MII_CS_PRO_BDI_BDI2_AnswerList
* include #bdi-bdi2-answer-1b from system MII_CS_PRO_BDI_BDI2_AnswerList

Advantages:

• Central code management
• Multiple ValueSet variants from a single CodeSystem
• Concept reusability

Reuse Across Questionnaires

Criterion: Same answer patterns in multiple instruments

Use case: Generic PRO severity scales (none/mild/moderate/severe) Advantages:

• Consistent terminology
• Central maintenance
• Harmonized data models

Complex Scoring Requirements

Criterion: Multiple score weights per concept, complex scoring rules

Example: BDI-II with variant answer weights (1a vs 1b) Implementation: CodeSystem properties for itemWeight management

Questionnaire Capabilities-Based Decisions

Criterion: Capability profiles require specific terminology approaches

Capabilities and terminology implications:

• Displayable = false, Calculatable = true: Requires answerValueSet for score calculation without display logic
• Displayable = true: Can use inline answerOption with rich display content
• Extractable = true: Requires correct itemWeight definitions for .weight() functions
• Multiple Capabilities: Inline answerOption offers maximum flexibility for display + calculation

BDI-II example:

* extension[capabilities].extension[displayable].valueBoolean = false
* extension[capabilities].extension[calculatable].valueBoolean = true
* item[=].answerValueSet = "http://www.medizininformatik-initiative.de/fhir/ext/modul-pro/ValueSet/mii-vs-pro-bdi-bdi2-short" // Scores without display dependency

MII Terminology Strategy

Criterion: No reliable international standards available, German specifics required

Strategic considerations:

• Full control over terminology lifecycle
• German healthcare system specifics
• Cultural adaptations of answer options
• Normative authority over PRO definitions

Decision Matrix

Visual Overview

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Implementation Examples

Example 1: PHQ-9 (LOINC + Inline)

* item[1].answerOption[0].valueCoding.system = $LNC
* item[1].answerOption[0].valueCoding.code = #LA6568-5
* item[1].answerOption[0].valueCoding.display = "Not at all"
* item[1].answerOption[0].valueCoding.display.extension[0].url = $hl7-translation
* item[1].answerOption[0].valueCoding.display.extension[0].extension[0].url = "lang"
* item[1].answerOption[0].valueCoding.display.extension[0].extension[0].valueCode = #de
* item[1].answerOption[0].valueCoding.display.extension[0].extension[1].url = "content"
* item[1].answerOption[0].valueCoding.display.extension[0].extension[1].valueString = "Ueberhaupt nicht"
* item[1].answerOption[0].extension.url = "http://hl7.org/fhir/StructureDefinition/ordinalValue"
* item[1].answerOption[0].extension.valueDecimal = 0

Example 2: BDI-II (MII CodeSystem + ValueSet)

// Questionnaire Item
* item[=].answerValueSet = "http://www.medizininformatik-initiative.de/fhir/ext/modul-pro/ValueSet/mii-vs-pro-bdi-bdi2-short"

// CodeSystem
CodeSystem: MII_CS_PRO_BDI_BDI2_AnswerList
* ^property[+].code = #ordinalValue
* ^property[=].type = #decimal
* #bdi-bdi2-answer-1a ^property[+].code = #ordinalValue
* #bdi-bdi2-answer-1a ^property[=].valueDecimal = 1

// ValueSet Short Form
ValueSet: MII_VS_PRO_BDI_BDI2_AnswerListShort
* include #bdi-bdi2-answer-0 from system MII_CS_PRO_BDI_BDI2_AnswerList
* include #bdi-bdi2-answer-1 from system MII_CS_PRO_BDI_BDI2_AnswerList

Example 3: EQ-5D-5L (Simple Inline)

* item[=].answerOption[+].valueCoding.display = "I have no problems in walking about"
* item[=].answerOption[=].valueCoding.code = #1
* item[=].answerOption[+].valueCoding.display = "I have slight problems in walking about"
* item[=].answerOption[=].valueCoding.code = #2

Calculated Expressions and .weight() Functions

Critical implementation requirement: FHIRPath .weight() functions require correct itemWeight definitions:

With Inline answerOption:

* item[=].answerOption[0].extension.url = "http://hl7.org/fhir/StructureDefinition/ordinalValue"
* item[=].answerOption[0].extension.valueDecimal = 0

With CodeSystem + ValueSet:

CodeSystem: MyCodeSystem
* ^property[+].code = #ordinalValue
* ^property[=].type = #decimal
* #answer-code ^property[+].code = #ordinalValue
* #answer-code ^property[=].valueDecimal = 0

Governance and Lifecycle Management

MII Terminology

Advantages:

• Full control over definitions
• German healthcare system specifics
• Coordinated evolution with MII standards
• Normative authority for German PRO implementations

Responsibilities:

• MII PRO Working Group: Terminology governance
• Implementers: Feedback and requirements
• MII Terminology Service: Distribution and maintenance

International Standards Integration

LOINC priority: Prefer LOINC where available and suitable Mapping strategies: ConceptMaps for MII to LOINC harmonization Future strategy: Gradual migration to international standards as they become available

Conclusion

The choice of terminology strategy is a strategic architectural decision that significantly impacts the long-term maintainability, interoperability, and scalability of PRO implementations.

Guiding principle: "International standards first, MII terminology where necessary, simple inline where appropriate"

This strategy enables leveraging the advantages of international interoperability while simultaneously addressing the specific requirements of the German healthcare system.