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MAP CDA to FHIR and Back

Oliver Egger, ahdis ag

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Who am I?

Oliver Egger

2015 - founder ahdis2003 - 2014 visionary AG, docbox2002 - 2003 Ecofin Research & Consulting AG1994 - 2001 SPEAG

2016 - lecturer BFH Bern, ZHAW Winterthur Medical informatics, Interoperability

HL7.chTechnical Manager, member hl7 since 2009

IHE SuisseDeputy Technical Manager since 2016, member since 2015

Dipl. Inf. ETH, ETH Zürich, 1996IHE XDS Advanced Training, 2015Certified HL7 CDA Specialist, 2015Certified Scrum Master, 2014NDK eHealthcare, Nottwil, 2009

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Learning Objectives Tutorial/Let’s Build

• Relation between CDA and FHIR documents• Approaches to map CDA to FHIR and back• Validate CDA with the FHIR CDA Logical Model• Using FHIRPath to extract information from CDA• Using FHIR Mapping Language to convert from CDA to FHIR

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Document Characteristics

• Persistence• Stewardship• Authentication• Wholeness• Human readable

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CDA – Clinical Document Architecture

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CDA projects in Europe?

• Austria: ELGA with 7 IG’s• Denmark: UPO, DK APD, PHRM-DK, DKQFDD, DK-QRD• Italy: 5 IG’s published, 4 IG’s in ballot• Switzerland: eHealth Suisse 3 IG’s• Europe: CDA IPS, Electronic Health Record Exchange Format

and many more in Finland, Netherlands, Germany, Norway …

http://www.hl7.eu/download/eun-09-2019.pdf

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How to implement CDA projects?

• CDA has a XSD Schema (not normative and allows extensions), todays programming languages can work with it• in Europe CDA projects are often developed with ART-DECOR (Output

Website, Schematron rules and HL7 ITS Templates) • MDHT: Model-Driven Health Tools (MDHT) open source project, UML

model-driven tools to create computable models• eHealth Connector, Swiss open source project: first using MDHT now

directly working with CDA Schema and ART-DECOR templates• Simple approach: templating for creating CDA’s and query language

(XPath) for getting specific data out of CDA

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FHIR – FAST Healthcare Interoperability Resources

• FHIR is fast for implementers, why?• Community and based on modern IT standards• Licensing issues / web-based standard which is searchable with examples• Reference implementations• Test servers• Validation Tools• Publishing Tools

• How this can be applied to implement CDA with FHIR tool stack?

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FHIR Documents

• FHIR resources can be used to build documents that represent a composition: a coherent set of information that is a statement of healthcare information.• First entry is a Composition Resource

• Equivalent to CDA header and narrative• Can be signed, authenticated, etc.• A FHIR document has the same basic principles as a CDA document

http://hl7.org/fhir/documents.html

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Documentsare Bundles

Observation Resource

Composition Resource

Section

Device Resource

Condition Resource

List Resource

<Bundle><entry>

<Composition /></entry> <entry>

<Observation /></entry><entry>

<Device /></entry><entry>

<List/></entry><entry>

<Condition/></entry>

</Bundle>

AttesterMetadata Section

Section

Source: https://github.com/FHIR/documents/tree/master/presentations/2019-01%20Webinars

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FHIR Documents, CDA

• Clinical document focus• Human readability approach• Clinical Statement vs. Resources• Templates and Profiles• CDA markup, xhtml• Discrete to human-readable linkages

https://www.hl7.org/fhir/comparison-cda.html

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Mapping from CDA to FHIR

• CDA Level 1: (Just metadata and text), map to Bundle/Composition• CDA Level 2: Coded sections, map to Bundle/Composition• CDA Level 3: Structured entries, map to entries in Bundle

Level 1, Level 2 can be done maybe 70% generic, there are some different or missing concepts or too general to mapLevel 3 general mapping hardly possible, can only be done on a profiled CDA (template), like C-CDA or a specific exchange format

Mappings should be done at the CDA template level rather than at the CDA specification

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Composition CDAMapping

http://hl7.org/fhir/composition-mappings.html

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Mapping Strategies

• CDA as FHIR Binary with DocumentReference for Metadatea• XSLT• Argonaut: CCDA on FHIR Project (April 2018, STU3)• CCDA to FHIR Project (September 2018)• CDA Logical Model with FHIR Mapping Language• Microsoft CDA Mapping• Google

FHIR documents can represent the same information as a CDA (see limitations of this approach from Marten Smits et al in:A comparison of two Detailed Clinical Model representations: FHIR and CDA

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Use CDA as documents (no mapping)

• DocumentReference Resource for Metadata (equivalent to XDS or CDA Header)• CDA Document as attachement, embedded in DocumentReference or

referenced to FHIR Binary Endpoint http://server.org/fhir/Binary/

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Mapping approaches

• C-CDA on FHIR Project http://hl7.org/fhir/us/ccda/index.html• C-CDA Mapping based on FHIR Mapping Language

(https://github.com/HL7/ccda-to-fhir)• CDA FHIR Maps for eMedication Switzerland:

https://github.com/hl7ch/cda-fhir-maps

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Mapping with the FHIR Mapping Language and CDA Logical Model

• https://www.hl7.org/fhir/mapping-language.html

CDA FHIRMappingEngine

MapsCDA

LogicalModel

17http://build.fhir.org/ig/HL7/cda-core-2.0/branches/master/index.html

FHIR Logical model CDA

• Logical Model is a description of CDA

• no API • datatypes are equivalent to FHIR • no FHIR resources • no query possibilities

• Logical Model can be used with the FHIR Mapping Language

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MedicationCard - Document

https://github.com/hl7ch/cda-fhir-maps/blob/master/input/maps/CdaChEmedMedicationCardDocumentToBundle.map

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Microsoft FHIR Converter

• using handlebartemplates

https://github.com/microsoft/FHIR-Converter

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Google CloudHealthcare DataHarmonization

• v2 to FHIR

https://github.com/GoogleCloudPlatform/healthcare-data-harmonization/blob/master/mapping_language/doc/reference.md

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Mapping with the FHIR Mapping Language and CDA Logical Model

• https://www.hl7.org/fhir/mapping-language.html

CDA FHIRMappingEngine

MapsCDA

LogicalModel

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FHIR Logical model CDA

• Introduction FHIR Logical Model• CDA Logical Model• Validating CDA• Conversion to JSON• Querying via FHIRPath• CDA Narrative conversion form xhtml and back with the Java Validator

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StructureDefinition

• The StructureDefinition resource describes a structure - a set of data element definitions, and their associated rules of usage. These structure definitions are used to describe both the content defined in the FHIR specification itself - Resources, data types, the underlying infrastructural types, and also are used to describe how these structures are used in implementations.• Note that as part of the specification itself, a

full set of structure definitions for all resources and data types is published.

http://hl7.org/fhir/structuredefinition.html

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Logical models based on StructureDefinitions

• StructureDefinitions can also be used to define any arbitrary structures that are a directed acyclic graph with typed nodes, where the primitive types are those defined by the FHIR specification.• This technique has many uses• Describing any arbitrary content model• Describing existing HL7 content models (e.g. v2, CDA) using FHIR• Describing common design patterns used in FHIR• Defining a content model to support the mapping language

http://hl7.org/fhir/structuredefinition.html#logical

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FHIR Logical model for CDA

• supports the CCDA on FHIR guide, and other CDA/FHIR mapping projects• Presented by Grahame at FHIR DevDays in 2016• https://github.com/HL7/cda-core-2.0• IG Publisher generates then the model: • http://build.fhir.org/ig/HL7/cda-core-

2.0/branches/master/index.html• Note: no official release yet

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V3 Datatypes

AD: PostalAddress

ANY: DataValue

BL: Boolean

CD: ConceptDescriptor

CE: CodedWithEquivalents

CO: CodedOrdinal

CR: ConceptRole

CS: CodedSimpleValue

CV: CodedValue

ED: EncapsulatedData

EIVL_TS: EventRelatedPeriodicInterval

EN: EntityName

EN: EntityName

II: InstanceIdentifier

INT: IntegerNumber

IVL_INT: Interval

IVL_PQ: Interval

IVL_TS: Interval

MO: MonetaryAmount

PIVL_TS: PeriodicIntervalOfTime

PQ: PhysicalQuantity

PQR: PhysicalQuantityRepresentation

QTY: Quantity

REAL: RealNumber

RTO_PQ_PQ: Ratio

SC: CharacterStringWithCode

ST: CharacterString

SXCM_TS: GeneralTimingSpecification

SXPR_TS: Component part of GTS

TEL: TelecommunicationAddress

TS: PointInTime

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Datatypes: ANY – CD - CE

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CDA classes

ClinicalDocument

Act

Authenticator

Author

AuthoringDevice

Authorization

AssignedAuthor

AssignedCustodian

AssignedEntity

AssociatedEntity

Birthplace

Component2

ComponentOf

Consent

Criterion

Custodian

CustodianOrganization

DataEnterer

Device

DocumentationOf

EncompassingEncounter

Encounter

Entity

ExternalAct

ExternalDocument

ExternalObservation

ExternalProcedure

Guardian

HealthCareFacility

Informant

InformationRecipient

InfrastructureRoot

InFulfillmentOf

IntendedRecipient

LabeledDrug

…

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CDA classes

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CDA & FHIR Logical Model

• attributes• type attributes in xml• text in xml elements• CDA narrative vs xhtml• V3 classes with id element and extension attribute • foreign namespaces• choice elements from CDA schema• granularity of model (e.g. EntryRelationship as Element and not as

only type)

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cda xml attributes

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text in xml elements: ST datatype

title.dataString

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CDA narrative vs xhtml

validator: internal conversion

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Summary CDA Logical Model

• Logical Model is a description of CDA• no API • datatypes are equivalent to FHIR • no FHIR resources • no query possibilities

• Logical Model can be used with the FHIR Mapping Language

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CDA and FHIR Validation

The HL7 FHIR Validator can validate with logical models, you need to provide the packagename (package.tgz instead of hl7.fhir.cda#current)

java -jar org.hl7.fhir.validation.cli.jar -version 4.0.1 -ig package.tgzresources/examples/cda-ch.xml

FHIR Validation tool Version 4.0.32-SNAPSHOT

.. connect to tx server @ http://tx.fhir.org

.. definitions from hl7.fhir.r4.core#4.0.1

+ .. load IG from package.tgz

.. validate [resources/examples/cda-ch.xml]

Success...validating resources/examples/cda-ch.xml: error:0 warn:0 info:20

https://github.com/ahdis/cda-core-2.0/releases/download/v0.0.3-dev/package.tgz

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CDA and FHIR ValidatorVisual Studio Code

1) Right click on file to validate and select validate with params

2) Add params –version 4.0.1 cda-core-2.0-pr.tgz

3) Output

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Convert CDA to JSON Logical Model representation

java -jar org.hl7.fhir.validation.cli.jar -version 4.0.1 -ig package.tgz -convert -output resources/examples/cda-original.json resources/examples/cda-original.xml

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Applying FHIRPath expressions to CDA documents

• FHIRPath is a path based navigation and extraction language, somewhat like XPath. • Operations are expressed in terms of the logical content of

hierarchical data models, and support traversal, selection and filtering of data. • Its design was influenced by the needs for path navigation, selection

and formulation of invariants in both HL7 Fast Healthcare Interoperability Resources (FHIR) and HL7 Clinical Quality Language (CQL).

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Applying FHIRPath expressions to CDA documents

java -jar org.hl7.fhir.validation.cli.jar -version 4.0.1 -ig package.tgz -fhirpathrecordTarget.patientRole.patient.name.given.dataString resources/examples/cda-original.xml

.. definitions from hl7.fhir.r4.core#4.0.1

(v4.0.1)

+ .. load IG from package.tgz

...evaluating recordTarget.patientRole.patient.name.given.dataString

Henry

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FHIRPath expressions to CDA documents

https://niquola.github.io/fhirpath-demo/#/

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FHIRPath expressions to CDA documents

FHIR tools with Visual Studio Code Extension

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Mapping with the FHIR Mapping Language and CDA Logical Model

• https://www.hl7.org/fhir/mapping-language.html

CDA FHIRMappingEngine

MapsCDA

LogicalModel

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FHIR Mapping Language

https://www.hl7.org/fhir/mapping-language.html

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Mapping Engines

• Java FHIR Mapping• Java Validator• matchbox (hapi-fhir, java, test.ahdis.ch/r4)

• C# FHIR Mapper https://vonk.fire.ly• JavaScript fhir-kit-mapping-language• Pascal

https://confluence.hl7.org/display/FHIR/Using+the+FHIR+Mapping+Language

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Mapping Authoring

• Define mapping instructions to transform the source content to the target content.• Use the mapping engine to create a

machine-readable representation of the mapping instructions in the form of a FHIR StructureMap resource.

https://confluence.hl7.org/display/FHIR/Using+the+FHIR+Mapping+Language

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Mapping Execution

• Store the source FHIR StructureMap resource on the FHIR Server.• Execute transformations - $transform - The

mapping engine requires:• The source content to transform.• The machine-readable representation of

the mapping instructions previously created.

• Store the generated target content (optional)

https://confluence.hl7.org/display/FHIR/Using+the+FHIR+Mapping+Language

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Mapping from CDA to FHIR

Mappings should be done at the CDA template level rather than at the CDA specification …

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Maps CDA to FHIR

• Data types: CDAtoFHIRTypes.map• CDA: CDAtoBundle.map• CDA-CH: CDAChtoBundle.map• MedicationCard:

CdaChEmedMedicationCardDocumentToBundle.map

https://github.com/hl7ch/cda-fhir-maps

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MedicationCard - Document

https://github.com/hl7ch/cda-fhir-maps/blob/master/input/maps/CdaChEmedMedicationCardDocumentToBundle.map

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MedicationCard – Document, Section

https://github.com/ahdis/cda-fhir-maps/blob/master/input/maps/CdaChEmedMedicationCardDocumentToBundle.map

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MedicationCard – Entry Level Template

https://github.com/hl7ch/cda-fhir-maps/blob/master/input/maps/CdaChEmedMedicationCardDocumentToBundle.map

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Example transformation

https://github.com/hl7ch/cda-fhir-maps/blob/master/input/maps/CdaChEmedMedicationCardDocumentToBundle.map

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Zulip Streams

• CDA• CCDA / FHIR mapping stream • cda to fhir• cda/publish• mapping-framework

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What did you learn?

• Relation between CDA and FHIR documents• Approaches to map CDA to FHIR and back• Validate CDA with the FHIR CDA Logical Model• Using FHIRPath to extract information from CDA• Using FHIR Mapping Language to convert from CDA to FHIR

Joint the Let’s build tomorrow to perform above steps yourself, same time as today!https://github.com/ahdis/cda-core-2.0/blob/develop/tutorial.md

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QA & Contact

• During DevDays, you can find / reach me here:• Via Whova App – Speaker’s Gallery• Email: oliver.egger@ahdis.ch• Twitter: @oliveregger