XML used for Healthcare Messaging and Electronic Health Record Communication

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XML used for Healthcare Messaging and Electronic
Health Record Communication

• David Markwell - Clinical Information
  Consultancy
• Andrew Hinchley - Communication Planning Ltd

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Three intertwined projects

• CEN TC251 Healthcare Informatics Standards
• ENV13606 - Prestandard for EHCR Communication
• Part 4 - Messages for exchange of information
• XML-EDI Project - using XML for EDI
• EU Information Society Initiative for
  Standardisation (ISIS)
• XMLEPR Project - validation of the message
• UK National Health Service andRoyal College of
  General Practitioners

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Three parallel objectives

• A standard message for health record transfer
• Investigate XML as a syntax for EDI
• Propose good practice guidelines for XML/EDI
• Identify benefits issues raised by XML/EDI
• Validation of a draft of ENV13606
• Confirm it meets UK NHS needs for GP to GP
  transfer of patient records
• Propose revisions where needed to meet needs
• Identify needs for implementation guidelines

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Background to healthcare record messages in the
XML/EDI project
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Background EHCR Communication Prestandards

• Part 1 - Extended Architecture
• A Standardised view of EHCR information
• Part 2 -Term List
• High-level categories annotations
• Part 3 - Distribution Rules
• A Standard way to express access rules
• Part 4 - Messages
• Standard messages for EHCR communication

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CEN TC251 Message Development Method
Scope Specification
Content Dependent
User requirements
Scenarios
Communication roles services
Domain Information Model
Syntax
General Message Description
Implementable Message Specification
Hierarchical GMD
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Proposed EHCRmessage data items
a type of
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EHCR message structure
1
specialised as
1
contains
1..
1..
specialised as
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Coding, terminology semantics

• Present healthcare data structures
• Allow use of a variety of coding schemes
• ENV13606 Part 2 Term List provides a minimum set
  of heading context terms
• Improved communication requires
• Standard terms, qualifiers and classifications
• Mapping between terms and classifications
• An interesting development
• Merger between the UK NHS Clinical Terms (Read
  Codes) and SNOMED-RT

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BackgroundHTML XML -- Chalk Cheese

• Is cheese extended chalk?

• Is XML extended HTML?

• Both are edible solids
• Both contain calcium

• Both based on SGML
• Both contain tags

• But
• Chalk is good for display
• Cheese is nourishing

• But
• HTML is a layout mark-up format
• XML represents data

• HTML uses fixed tags
• XML enables tags to be purpose-defined

• Chalk is hard
• Cheese soft or resilient

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Mapping from UML models of messages to XML
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Mapping message models for implementation

• Mapping to EDIFACT
• Difficult manual process
• Conformance to models unverifiable
• Mapping to XML
• Automatable process
• Preserves structure of model
• Verifiable conformance
• Easier profiling
• Opportunity for ISO led convergence with HL7

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Mapping - General Points

• Message Development Methods lead to syntax
  independent models
• Limits of automation
• Extra information needed in models to support
  maps
• UML may not be rich enough!
• Retain links back to the model

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Mapping messages or models

• XML to represent UML models
• generalised DTD possible
• content represents classes relationships
• XML to represent information storage
• Freer use of XML cross-references (e.g. ID
  IDREF)
• Messaging environment
• some relationships by nested containment
• others refer to instance Ids not in message

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Mapping classes

• Concrete classes
• Mapped to XML-Elements
• Abstract (generalised) classes
• Represented as XML-Entities
• Add to the content model
• In XML-Elements for classes specialised from them
• Create a choice structure for specialisations
• In XML-Elements that include the generalisation

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Mapping attributes

• Most attributes mapped to an appropriate
  XML-Element
• Attributes mapped to XML-Attributes include
• Metadata such as
• Coding scheme identifier for a code value
• The language of the content (xmllang)
• Status or typing data that affects processing
• Possibly for unique IDs ("ID" "IDREF)
• Enumerated data types (pragmatic reasons)

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Mapping common classes

• Common Class XML-Element
• Example
• PersonName" in "PatientMatchingInfo
• OR
• XML-Element specific to each attribute with
  derived content
• Example
• "AlternativeName" in "PatientMatchingInfo

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Mapping to DTDs or XML Schema

• Mapping to DTDs now because they are
• Stable
• Well supported by software
• Schema proposals offer major advantages
• More flexible constraints
• Data Typing
• Archetypes
• Extensibility
• Mapping to Schemas next logical step

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XML/EDI in use to validate the healthcare record
message for UK GP to GP communication
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Background to XMLEPRUK NHS GP computing

• The situation
• 95 of UK GPs have computers
• 50 use these computers for clinical patient
  records
• GP computer systems in the UK
• Three major suppliers of GP systems
• Twelve widely used systems or versions
• Different record structures
• None transfer records when patients move

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Clinical validation

• What is clinical validation of a message?
• Suppliers of diverse systems map real record from
  their systems into the message structure
• Clinical professionals review original records
  and the messages generated
• Look for inconsistencies, missing or added info.
• Determine whether the representations are safe
• XML used for validation because it offered
• Direct mapping from message models
• Freely available viewers and software libraries

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The validation process
Compare
Observe
Comment
Clinicians
Viewer
GP system
PT29 Provide EHCR
Message
Mapping
Experts
Export
Layout
Provide EHCR
DTD
Instance of XML
message/document
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XMLEPR projectValidation of GP to GP
communication

• Supplier results
• Four leading GP system suppliers populated the
  messages with information from their systems
• Found XML learning-curve/implementation easier
  than EDIFACT
• Viewers used for clinical validation
• IE5
• XML-Notepad
• Specialised viewer developed in the project

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Results of validation

• The Provide EHCR message is substantially able to
  convey the information present in a majority of
  existing GP Electronic Patient Records (in the
  UK)
• Some weaknesses in the draft message proposal
• Reported as formal comments to the Project Team
  responsible for the draft prestandard
• All these comments were accepted and resulted
  either in changes to the message or
  clarifications in the documentation
• Further validation, piloting and implementation
  recommended to the UK NHS

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Other results and progress

• EHCR Communication Prestandards
• Accepted by ballot on 29 June 1999
• Comments from use will be monitored for the next
  revision in 2-3 years time
• ISIS XML/EDI project continues to end of year
• Further recommendations and demonstrations
  expected
• ISO TC215 Health Informatics
• May draft guidelines for use of XML in messaging

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References

• Material about the message and links to other
  sites
• http//www.clinical-info.co.uk
• CEN TC251 Standards including ENV13606
• http//www.centc251.org
• XMLEPR project
• http//www.CommunicationsPlanning.co.uk/infopages
• Other XML/EDI information
• http//www.tieke.fi/isis-xmledi

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Healthcare uses of XML
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User Interface
User Interface
View
Enter
View
Enter
Application
Application
Read
Write
Read
Write
Data store
Data store
EDI Interface
EDI Interface
Messages in XML
Messages in XML
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User Interface
User Interface
Browser
View
Enter
View
Enter
API
Application
Application
XML document
Read
Write
Read
Write
Data store
XML publisher
Data store
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User Interface
Browser
View
Enter
API
XML document
Application
XML publisher
Extract
Read
Write
Extract
Extract
Data store
Data store
Data store
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User Interface
Browser
View
Enter
API
XML document
Application
Browsable reference material on web sites
Read
Write
Data store
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User Interface
User Interface
Browser
View
Enter
View
Enter
API
Application
Application
XML
Read
Write
Read
Write
Data store
Data store
XML archiver
XML archive reader
Archive
XML
XML
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User Interface
User Interface
Browser
View
Enter
View
Enter
API
Application
Application
XML document
Read
Write
Read
Write
Data store as XML documents
Data store
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User Interface
User Interface
View
Enter
View
Enter
Application
Application
Read
Write
Read
Write
Data store as XML documents
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References

• Material about the message and links to other
  sites
• http//www.clinical-info.co.uk
• CEN TC251 Standards including ENV13606
• http//www.centc251.org
• XMLEPR project
• http//www.CommunicationsPlanning.co.uk/infopages
• Other XML/EDI information
• http//www.tieke.fi/isis-xmledi