SNOMED CT and deployment in the UK

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SNOMED CT and deployment in the UK

• Ian Arrowsmith, UKTC Chief Terminologist
• Andrew Sunley UKTC Business Manager
• July 2008

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Structure of session

• Part 1
• Introduction to SNOMED CT
• History of coding
• SNOMED CT structure and content
• Benefits/uses
• Part 2
• UK Terminology Centre and SNOMED CT
• Structure and organisation
• UK tailoring of SNOMED CT

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Part 1

• History of coding.

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London Bills of Mortalityevery Thursday from
1603 until the 1830s
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Aggregated Statistics 1665
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Manchester MercuryJanuary 1st 1754

• Executed 18
• Found Dead 34
• Frighted 2
• Kill'd by falls and other accidents 55
• Kill'd themselves 36
• Murdered 3
• Overlaid 40
• Poisoned 1
• Scalded 5
• Smothered 1
• Stabbed 1
• Starved 7
• Suffocated 5

Aged 1456 Consumption 3915 Convulsion
5977 Dropsy 794 Fevers 2292 Smallpox 774 Teeth
961 Bit by mad dogs 3 Broken Limbs 5 Bruised
5 Burnt 9 Drowned 86 Excessive Drinking 15
List of diseases casualties this year 19276
burials 15444 christenings Deaths by centile
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Quotation

• I am fain to sum up with an urgent appeal for
  adopting some uniform system of publishing the
  statistical records of hospitals. There is a
  growing conviction that in all hospitals, even in
  those which are best conducted, there is a great
  and unnecessary waste of life In attempting to
  arrive at the truth, I have applied everywhere
  for information, but in scarcely an instance have
  I been able to obtain hospital records fit for
  any purposes of comparison If wisely used,
  these improved statistics would tell us more of
  the relative value of particular operations and
  modes of treatment than we have means of
  ascertaining at present.

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Florence Nightingale

• Defined 3 Outcome groups (1856)
• Relieved
• Not Relieved
• Died

Notes on Hospitals, London Longman, Green,
Roberts, Longman and Green 1863
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Dr William Farr 1855

• Developed the International Listing of Causes of
  Death
• Adopted by World Health Organisation (WHO) in
  1948
• Evolved into the International Statistical
  Classification of Diseases (ICD)

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Contemporary history (origins of SNOMED CT)

• College of American Pathologists
• SNOMED 2 (1979) (Most widely adopted version in
  pathology systems worldwide)
• SNOMED 3 International (1993)
• SNOMED RT Reference Terminology (2000)
• United Kingdom National Health Service??Read
  Codes 4-byte (1984)
• Read Codes 2 5-byte (1988)
• Clinical Terms version 3 CTV3 (Read Codes)
  (1999)
• SNOMED CT represents a true confluence
• All codes in SNOMED RT and CTV3 are included

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SNOMED CT
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Introduction

• Systematized Nomenclature of Medicine
• SNOMED CT- Clinical Terms
• Developed by NHS and the College of American
  Pathologists (CAP)
• Merges the content of the NHSs Clinical Terms
  Version 3 (The Read Codes) with CAPs SNOMED
  Reference Terminology (SNOMED RT)
• Demo and quiz

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SNOMED CT overview

• Comprehensive clinical terminology that is used
  to
• Code
• Retrieve, and
• Analyze clinical data
• Comprises of
• Concepts
• Terms
• Relationships
• All necessary to precisely represent clinical
  information across the scope of health care.

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What is a clinical terminology

• A terminology
• A structured collection of terms
• A clinical terminology
• A terminology consisting of terms used in health
  health care
• In SNOMED CT.
• Terms attached to concept codes with multiple
  terms per code
• structured according to logic-based
  representation of meanings

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Basic Elements of SNOMED CT

• Concepts
• The basic units of SNOMED CT
• Descriptions
• These relate terms that name the concepts to the
  concepts themselves. Each concept has at least
  two Descriptions
• Hierarchies
• Concepts are organized into twenty SNOMED CT
  hierarchies (in UK extension). Each hierarchy has
  sub-hierarchies within it
• Relationships
• Relationships are the connections between
  concepts in SNOMED CT
• Other components
• Subsets
• Extensions
• Mappings

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Concepts

• Represent distinct clinical meanings
• Identified by a unique numeric identifier
  (Concept ID) that never changes and a unique
  human readable name (Fully Specified Name)
• Associated with each concept is a set of
  relationships (the logical definition) and a
  set of names or terms
• Differing levels of granularity
• There are currently around 400,000 terms in
  SNOMED CT

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Concept codes

• One code per meaning, one meaning per code
• Strings of digits, length 6 to18 (most commonly 8
  or 9 digits)
• 22298006 means myocardial infarction (MI)
• 399211009 means past history of MI
• Codes vs Concepts vs Real things
• Concepts are in peoples heads
• Codes are in the terminology
• The codes refer to real things in the real world

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Descriptions

• Concept descriptions relate the terms or names of
  a SNOMED CT concept to the concept itself.
• Term in this context means a phrase used to
  name a concept.
• Each of these descriptions has a unique
  Description ID, but all of these descriptions are
  associated with a single concept (and a single
  Concept ID).
• Descriptions are an important interface property
  because they give end users the flexibility to
  use terms that they are familiar with.
• The Concept ID ties terms with the same meaning
  together to aid consistent interpretation and
  retrieval.

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Description types

• Preferred Term
• The most common word or phrase used by clinicians
  to name a concept
• Fully Specified Name
• Provides an unambiguous way to name a concept
• Synonyms
• The rest of the names that may be used for a
  concept

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Example of components

• Some of the descriptions associated with
  ConceptID 22298006
• Fully Specified Name Myocardial infarction
  (disorder)
• DescriptionID 751689013
• Preferred term Myocardial infarction
• DescriptionID 37436014
• Synonym Cardiac infarction
• DescriptionID 37442013
• Synonym Heart attack
• DescriptionID 37443015
• Synonym Infarction of heart
• DescriptionID 37441018

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SNOMED CT is large

• 283,000 Active concept codes
• 732,000 Active terms (descriptions)
• 923,000 Active defining relationships
• If you spent 1 minute examining each description,
• Working 40 hrs/week (2400 minutes/week), it would
  take 305 weeks (6 years) to examine all the
  active descriptions
• Scale is a major issue in development, use and
  maintenance

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Demo Clue Browser

• Think of a term.

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Words and meaning

• Its not what you say, its what you mean
• The meanings of words and phrases change
• In context
• Between places
• Between disciplines and specialties
• Between different times

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The problem with words and meaning

• Does the leg mean the same as the lower limb?
• Thats what the average person assumes
• Health professionals also often use the word
  leg in this way
• But medical dictionaries take a different view
• Stedmans the segment of the inferior limb
  between the knee and the ankle
• Dorlands that section of the lower limb
  between the knee and ankle
• Ordinary dictionaries recognise both meanings

Some formal definitions conflict with ordinary
usage
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Use of English in context

• Dressing (oneself)
• Dressing (e.g. a bandage)
• Dressing (assisting the person to dress)
• Dressing (of wound)

• Dressing (observable entity) parent personal
  care activity
• Dressing, device (physical object)
• Dressing patient (procedure)
• Dressing of wound (procedure)

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Top-level hierarchies (October 2007)
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Exercise - Hierarchies

• Hierarchy
• Clinical Finding
• Procedure
• Observable Entity
• Body Structure
• Organism
• Substance
• Specimen
• Physical Object
• Physical Force
• Events

• Example
• Gravity
• Dust
• Entire Liver
• Clean Catch Urine
• Pneumonia
• Prosthesis
• Motor Vehicle Accident
• Biopsy of Lung
• Tumour Size
• Felis Silvestris (cat)

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Relationships

• The connections between concepts, several types
• Definitional
• necessarily true about the concept
• Relationships characterise concepts and give them
  their meaning
• The list of relationships for a particular
  concept makes up the logical definition of that
  concept
• Hierarchies constructed by Is_A relationships
• Qualifiers may be added to specialize the
  concept
• Historical provides a pointer to current
  concepts from retired
• Additional allows non-definitional information
  to be distributed

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IS-A relationships

• SNOMED CTs hierarchies consist entirely of IS-A
  relationships
• IS-A relationships in the Inflammatory disorder
  hierarchy
• Lumbar discitis IS-A Discitis
• Discitis IS-A Arthritis
• Arthritis IS-A Inflammatory disorder
• Inflammatory disorder IS-A Disease
• Some concepts have more than one IS-A
  relationship. These concepts have parent concepts
  in more than one hierarchy
• Lumbar discitis IS-A Discitis
• Lumbar discitis IS-A Disorder of back

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Procedure
IS_A
Procedure on lymph node
IS_A
Biopsy of lymph node
IS_A
Surgical biopsy of lymph node
IS_A
Excisional biopsy of lymph node
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SNOMED CT Concept
Disease
Disease of respiratory system
Infectious disease
Disease of lung
Pneumonia
Infective pneumonia
Bacterial infectious disease
Bacterial pneumonia
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Exercise - relationships

• Is a, Part of, Precedes, Follows

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Answers
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Attribute Relationships

• Characterise and specify concepts
• An example of an attribute is FINDING-SITE, which
  is used to further specify Disease concepts

e.g. part of the logical definition of the
concept Pneumonia in SNOMED CT is Concept
Pneumonia Attribute FINDING-SITE Value of
attribute Lung structure
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Attribute Relationships
IS A ...
IS A ...
finding site
ATTRIBUTE
lower limbstructure
IS A ...
IS A ...
finding site
ATTRIBUTE
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Pre and post coordination

• Pre-coordination is complete enumeration of
  clinical notion within release (single code)
• Eg acute pneumococcal bronchitis
• Post-coordination is user selected combination of
  concepts post-release (multiple codes and
  according to rules)
• Eg bronchitis course acute causative agent
  Streptococcus pneumoniae
• Both alternatives must be equivalent

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Motivation for post-coordination

• Desirable characteristic size
• Completeness of coverage by Concepts
• Completeness of coverage by potential to
  represent concepts (as post-coordinated
  Expressions)
• Editorial/design principles
• Elective economy of distributed data, e.g.
• Laterality
• Severity

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Post coordination rules

• Only certain types of concepts can be combined
• Must not permit
• vibration white finger
• 64572001 disease (disorder)
• 33679000vibration
• 371251000white
• 7569003finger
• It does not compute as 234034005 vibration white
  finger (disorder)
• - a secondary form of Raynaud's disease, an
  industrial injury triggered by continuous use of
  vibrating hand-held machinery

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Clue browser demo 2

• Defining attributes and qualifiers
• Cholecystectomy (procedure)
• Acute pneumococcal bronchitis (finding)

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Additional components features

• Cross Maps
• Subsets
• Extensions

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Cross Maps

• Cross mapping involves linking SNOMED CT to other
  terminologies
• Each cross map has a direction, either from
  SNOMED to the other, or vice versa.
• Archetypal crossmap is from SNOMED to ICD 10
• Usual use case for ICD
• I have a record. It needs to be assigned the
  right code.
• NOS and NEC are meaningful and necessary
• Usual use case for SNOMED
• I have a patient. I can document all that is
  relevant, and my EHR will attach codes to much of
  it (not all).
• NOS and NEC are meaningless

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Subsets

• A collection of terminology, selected and
  grouped for a particular purpose
• May be composed of anything from a single
  component to the entire set of concepts,
  descriptions or relationships
• Commonly needed for
• Data quality improvement
• Message field validation
• Simplified data entry and retrieval
• Elimination of noise

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Extensions

• SNOMED CT Identifiers allow for a part of the
  code to identify a Namespace
• A namespace is controlled by an organization
  other than IHTSDO eg Nation (UK)
• Extensions should add content that is not
  required in the international release,
  realm-specific content
• Multnomah County (Oregon) jail cell number
• Leave granted under the Mental Health Act 1983
  (England and Wales)

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UK extensions

• UK clinical and admin extension
• UK drug extension (dmd)
• Regional extensions
• Supplier extensions

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Uses and benefits of SNOMED CT
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What does it do?

• Nothing, it just sits there
• ..until incorporated into software systems
• Really
• It enables semantic interoperability (when
  implemented in an electronic health record)
• Supports implementation of electronic health
  records
• Decision support systems
• Makes records systematically maintainable,
  sharable

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Uses of SNOMED CT

• Representation of health information
• Indexing retrieval of health information
  generally
• Recording health care of individuals with
  fidelity to the clinical situation
• Record retrieval analysis based on meaning
• Important for decision support applications
• More specific examples
• Public health reporting infectious diseases,
  cancer, biosurveillance
• Reminders and alerts for preventive care

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Why is SNOMED CT relevant in the NHS

• SNOMED CT is an enabler for
• Cross Boundary Care
• Regional
• National
• International
• Consistent retrieval and analysis

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Making SNOMED Usable

• Requires design and selection of usable
  components
• Requires hiding some of the complexity from the
  users
• Requires software that enables the users to
  accomplish their goals

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Where do the codes go in a record

• Statements in EHRs
• Electronic health record is made up of a series
  of statements
• Codes are the values for fields/slots in the
  information model
• Codes from the terminology fill in some or all of
  the statement body
• Information model determines the fields/slots
  available
• Coordination required to avoid gaps overlaps
  between terminology model and the information
  model

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Electronic Healthcare Records

• SNOMED CT must be used in electronic healthcare
  applications
• Needed in conjunction with other standards
• Is not plug and play
• Most clinicians should neither know nor care
• How many digits are in a concept identifier
• How many concepts are in SNOMED CT
• How descriptions and relationships are tied to
  concepts

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What clinicians care about is.

• Clinical records they use meet their needs
• Record system components that work together
  reliably
• Being able to easily express the information they
  wish to enter in a patient record
• Being able to retrieve information to support
  delivery of care or for secondary uses with a
  minimum of extra effort
• David Markwell, Chair of former SNOMED CT Concept
  Model Working Group

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Benefits of an Electronic Health Record

• Reduced storage costs
• Can be accessed from many places
• Can be transferred quickly
• It is legible

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Benefits of a Structured Record

• Can display logical progression of clinical data
• Can retrieve clinical data based on situation or
  author
• Allows clinical data items to be transmitted
  longitudinally through a patients record

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Benefits of using a Controlled Clinical
Vocabulary

• Point of care uses-
• The ability to search records for clinical
  information
• Identification of patients who match a given set
  of criteria
• Provision of decision support
• Aggregation uses-
• Public health monitoring
• Outcomes analysis
• Performance analysis

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Benefits of using SNOMED CT

• Provides a consistent terminology across all care
  domains
• Allows precise recording of clinical information
• Has an inherent structure/model
• Is a developing international standard

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Is SNOMED CT Perfect?

• The man who makes no mistakes does not usually
  make anything.
• E J Phelps (1822 - 1900)
• so SNOMED CT is not perfect
• The goal is fitness for purpose not perfection

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Agenda Part 2

• SNOMED CT in an International Context
• Governance
• Licensing
• Product Distribution
• Useful Links

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IHTSDO Vision
The IHTSDO seeks to improve the health of
humankind generally by owning, distributing,
operating and developing suitable health
terminology products.   This improvement is to
be achieved through the sharing of more accurate
clinical and related health information, allowing
the implementation of semantically accurate
health records that are interoperable. Support to
Association Members and Licensees is to be
provided on a global basis allowing the pooling
of resources to achieve shared benefits.
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IHTSDO in Context
Australia, Canada (English), Denmark, Lithuania,
The Netherlands, New Zealand, Sweden, United
Kingdom, United States
Healthcare Users
Term Submissions License fees
Members
International Edition Guidance
No-cost licensing (in member jurisdictions)
IHTSDO
Services
WHO, HL7, Loinc, ISO, CEN
College of American Pathologists
Fees
Harmonisation Collaboration
Requests Fees
Other SDOs
Affiliates
Licenses
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Service Layers
Australia, Canada (English), Denmark, Lithuania,
The Netherlands, New Zealand, Sweden, United
Kingdom, United States
Users
Members
IHTSDO
Software Suppliers, LSPs, Trusts, Work Programmes
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IHTSDO Governance
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Member United Kingdom
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Role of a NPMC
Suppliers Embed/use codes within systems
design and interface messages

• National Admin codes (NACS)
• ICD/OPCS
• Read Codes
• NHS Data Dictionary
• Spine Directory Service (SDS)
• dmd
• SNOMED CT

• National Product Management Centre
• Governance,
• Creation,
• Maintenance,
• Distribution
• Guidance

Systems deployed
Users feedback to suppliers any problems
Suppliers verify if problem is with their
systems or codes need changing?
Via LSP/NPfIT helpdesks
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UKTC Context
ETP, SCR, PDS, CB, NMEPfIT, SPfIT, LPfIT
Term Submissions License fees Governance input
IHTSDO
Work Programmes
Requests
International Edition Guidance
Terms Subsets Advice
Education
UKTC
Clinical Community
Advice Governance
Requests
UK SNOMED CT edition Terms Subsets Advice
Suppliers
Harmonisation Integration
Other Standards
HL7, openEHR, ICD10, OPCS, Data Dictionary, DMD
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UKTC Governance
England, Northern Ireland, Scotland, Wales
UKTC Governance Board
UKTC Management Team
Implementation Forum
Combined Committee
Projects
Projects
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UKTC obligations to IHTSDO

• Manage product within its territory
• Liaise with Association
• Licensing and Distribution
• QA and conformance with Association standards
• Issues tracking
• Change control
• Monitoring IP (products, trademarks, etc)

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UKTC Governance Board

• 1 x representative (England, Scotland, Ireland,
  Wales)
• Head of UKTC
• Chief Terminologist
• Chief Technology Officer
• Chief Quality Assurance Officer
• Board appointees
• General Assembly Rep chair
• IHTSDO management rep, when needed
• Two other appointees, at board discretion

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UKTC Governance Board responsibilities

• Assure compliance with IHTSDO Articles
• Agree and approve services of UKTC
• Business plan
• Policies
• Licensing
• Financing
• Additional products and services
• Forums
• Ensure UK issues addressed through IHTSDO

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Timetabling

• IHTSDO Committee Meetings approx Quarterly face
  to face and interims via Teleconference
• Quarterly UK Governance Board meets
• Implementation Forum meets bi-monthly
• UKTC Combined Committee Meeting T.B.C.

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UKTC Services

• Development/Maintenance
• Technical Infrastructure
• Implementation
• Planning
• Resourcing
• Working groups
• Committees

• Knowledge management
• Documentation
• Web
• Training
• Legal
• Liaison with IHTSDO
• Secure collaboration

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UKTC Development Maintenance

• Licensing
• Authoring of SNOMED, Read, etc
• Cross mapping
• Clinical subsets for areas of national
  significance
• Home Countries
• Internationalisation (IHTSDO)
• Help Desk datastandards_at_nhs.net

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UKTC Technical Infrastructure

• Authoring Mapping
• Quality Assurance
• Publication
• Distribution (TRUD)
• Tooling (subsets, browsers, etc)
• Web presence

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UKTC - Implementation

• Design guidance and compliance
• Deployment roadmap
• Technical consultancy
• Data migration
• Single contact datastandards_at_nhs.net
• Education and Training

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UKTC is hosted by Data Standards Products
DSP
Data Dictionary
Interoperability Specifications
Terminology Centre
Consulting
Messaging Clinical Content Technical
SNOMED CT Read OPCS ICD10 DMD Cross
Maps Technical
Assurance Harmonisation Strategy
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Data Standards and Products in the National
Programme
DSP provide a broad range of services to all
development programmes in the National Programme
for IT, and to the NHS in General
Development Programmes
ETP
CB
PBR
SUS
SCR
Content Modelling (CEN13606, openEHR)
Data Dictionary (UML, Commissioning Data Sets)
Data Standards And Products
Messaging (HL7 V3, CDA)
Terminologies and Classifications (SNOMED CT,
Read, ICD10, OPCS)
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DSP Mission
To develop, maintain and support a comprehensive
range of clinically-related data standards that
effectively support healthcare within the NHS in
an integrated and holistic manner, facilitating
the delivery of a full longitudinal healthcare
record for patients that can support a diverse
set of secondary uses.
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How will SNOMED CT become the terminology
standard for the NHS

• Interoperability specifications
• MIM
• Content Models
• Data Dictionary
• Formal standards - ISB
• Supplier Adoption and Contracts
• Education and Advice
• Implementation Forum
• Training Programme

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Licensing

• Core /or UK extension release - no charge
• Access to all UK derivatives and extensions
  e.g. Diagnostic imaging
• Electronic registration/acceptance/distribution

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Licensing Model

• .

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National Products combined Release

• National admin Codes (NACS)
• ICD / OPCS
• Read codes/ Read Drugs
• NHS Data Dictionary
• Spine Directory Service (SDS)
• dm d
• SNOMED CT (UK Edition)

• Bi annual Release Cycle
• April
• October
• Core Jan/July

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SNOMED CT UK Edition

• SNOMED CT Core
• UK Extension Clinical Drugs
• Concepts, Descriptions, Relationships
• Cross maps ICD, OPCS
• Subsets
• Developers Toolkit
• Documentation Release Overview, TRG , TIG,
  User Guide

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Subsets - Approach

• Central supervision/overview
• Delegation/devolution of responsibility
• Dissemination of best practice
• Non-duplication of effort
• Provision of appropriate
• Tools
• Processes
• Resources
• Training

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http//termrequest.connectingforhealth.nhs.uk/regi
stry/subset/
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Subset ApproachOn-going management

• Must be in line with release cycle
• Local subsets
• Managed locally
• National externally managed subsets
• Managed by owner/creator or representative body
  e.g. subsets to support MiM
• National formal subsets
• Formal management to address nature and dynamism
• Formal processes and structures
• Appropriate stakeholders
• ISB approval

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Challenges Release Timeline

• Synchronisation with SNOMED CT Core
• 10 working day lead time for release go live
• Synchronisation of all Release components
• Read Codes/ Read Drugs
• Cross maps insufficient time to map new core
  concepts
• Subsets involvement of owner review body small
  window of opportunity

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Terminology Reference-data Update Distribution -
TRUD

• Electronic distribution
• Improved security
• Defined relative responsibilities
• Agreed service levels
• Acknowledged delivery
• Facility for out of cycle/ad hoc releases
• Exception handling

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Benefits

• Replace media distribution
• Licensing model built into the TRUD Application
• Better communication with organisations
• Better reporting, such as download stats
• Central location for all DSP terminology
  distribution

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Current Main Distributions

• Launched June 28th 2007
• Live distribution of Combined Bi-annual Release
• Monthly dmd (and bonus files) releases
• Monthly READ Drugs release
• Weekly PPD dmd release
• SDS (NACS) Quarterly releases

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Future Distributions

• Planned
• ICD10/OPCS4 Currently Jan 2009
• Possible
• Data Dictionary
• CUI Abbreviations manager
• MIM Messaging Implementation Manual

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TRUD - Numbers

• Media distribution figures at the last media
  release
• TRUD DVD 20
• SDS(NACS) 780 (half nhs half non nhs)
• READ 500, READ Browser 1550
• SNOMED 450
• OPCS ICD - 500

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https//www.uktcregistration.nss.cfh.nhs.uk/trud/
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TRUD - Usability
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Summary

• SNOMED CT in an International Context
• Governance
• Licensing
• UK Product Distribution
• Useful Links

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http//www.connectingforhealth.nhs.uk/systemsandse
rvices/data
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Further SNOMED Information

• www.ihtsdo.org
• http//www.connectingforhealth.nhs.uk/systemsandse
  rvices/data
• Help Desk datastandards_at_nhs.net
• https//www.uktcregistration.nss.cfh.nhs.uk/trud/
• http//termrequest.connectingforhealth.nhs.uk/regi
  stry/subset/

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Questions

• ????