SNOMED CT and other healthcare terminology standards: competition or cooperation? SNOMED CT in relation to LOINC, ICD, ICPC and other terminologies. Robert Hausam, Hausam Consulting LLC SNOMED CT 2019 -seminaari (29.3.2019

1. SNOMED CT and Other Healthcare
Terminology Standards:
Competition or Cooperation?
SNOMED CT in relation to LOINC, ICD, ICPC and other
terminologies
Robert Hausam MD
2019-03-29

2. Who am I?
◼ Rob Hausam MD
◼ Consultant in Clinical Informatics
◼ Family Physician, Electrical/Computer Engineer
◼ Active in HL7 and SNOMED International (IHTSDO)
➢ Co-chair of HL7 Vocabulary and Orders and Observations Work
Groups
➢ FHIR Core Team member, Co-lead FHIR Terminology Services
Connectathon track
➢ HL7 Co-lead of SNOMED on FHIR project (joint SNOMED Int. & HL7)
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3. Level Set
◼ If we want to discuss terminologies we need to get our
terminology straight! Right?
◼ What’s the source of truth?
◼ Standards Knowledge Management Tool (SKMT)
➢ Joint Initiative for Global Standards Harmonization
Health Informatics Document Registry and Glossary
➢ http://www.skmtglossary.org/
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4. SKMT Developers / Sponsors
◼ Developers
➢ Collaborative Research for Effective Diagnostics (CRED)
➢ Global eHealth Collaborative (GeHCO)
◼ Sponsors
➢ CRED (Collaborative Research for Effective Diagnosis)
➢ Global eHealth Collaborative (GeHCO)
➢ CIHI (Canadian Institute for Health Information)
➢ Canada Health Infoway
➢ Université de Sherbrooke
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5. Terminology, Vocabulary, or
Classification?
◼ Terminology
➢ set of terms representing a system of concepts within a
specified domain
➢ set of designations belonging to one special language
➢ set of designations within a subject field
➢ set of terms belonging to one special language
➢ science studying the structure, formation, development, usage and
management of terminologies in various subject fields
➢ structured, human and machine-readable representation of concepts
➢ language, words and terms used in a specific domain
5

6. ◼ Clinical terminology
➢ terminology required directly or indirectly to describe health conditions
and healthcare activities
6
Terminology, Vocabulary, or
Classification?

7. ◼ Reference terminology
➢ set of atomic level designations structured to support representations
of both simple and compositional concepts independent of human
language (within machine)
7
Terminology, Vocabulary, or
Classification?

8. ◼ Vocabulary
➢ terminological dictionary which contains designations and definitions
from one or more specific subject fields
➢ sum or stock of words employed by a language, group, individual
work or in a field of knowledge
8
Terminology, Vocabulary, or
Classification?

9. ◼ Classification
➢ exhaustive set of mutually exclusive categories to aggregate data at a
pre-prescribed level of specialization for a specific purpose
➢ terminology which aggregates data at a prescribed level of
abstraction for a particular domain
➢ terminological concept system connected by generic relations
◼ Classification system
➢ a terminological resource which has characteristics of mutual
exclusiveness and exhaustiveness to aggregate data where each pre-
prescribed level of specialization for a specific purpose
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Terminology, Vocabulary, or
Classification?

10. ◼ Classification (from SNOMED Int.)
➢ A classification groups diseases and other health issues into categories
based on similar properties. These categories may group by type of
disease, body system or anatomy, are often hierarchical (e.g. acute through
to chronic illness) and are ‘exhaustive’ which means almost all terms can be
classified through use of categories like NEC ‘not elsewhere classified’. A
classification has rules and standards to be followed when assigning codes,
and often has an index directing to the correct code assignment.
Classifications are used for statistics, epidemiology, audit, planning,
financial billing and other use cases where amalgamated data is required.
ICD-10 and ICPC are classifications as they have the characteristics noted
above.
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Terminology, Vocabulary, or
Classification?

11. More on this
◼ From the Australian Digital Health Agency
➢ Terminology vs Classification
◼ Terminology
➢ A clinical terminology is a structured vocabulary used in clinical
practice to accurately describe the care and treatment of patients
◼ Classification
➢ A classification is a structured way of organising information into
standard groupings
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12. And One More Thing …
◼ As is frequently asserted …
◼ And documented in the FHIR CodeSystemHierarchyMeaning
code system:
◼ ‘classified-with’
➢ Child concepts in the hierarchy may have only one parent, and there
is a presumption that the code system is a "closed world" meaning all
things must be in the hierarchy. This results in concepts such as "not
otherwise classified.".
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13. With that in mind …
◼ Let’s look at some terminologies
◼ Which ones should we look at in relation to SNOMED CT?
➢ LOINC
➢ ICD-10
➢ ICPC
➢ Others?
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14. SNOMED CT
◼ Is the most comprehensive, multilingual clinical healthcare
terminology in the world
◼ Is a resource with comprehensive, scientifically validated
clinical content
◼ Enables consistent representation of clinical content in
electronic health records
◼ Is mapped to other international standards
◼ Is in use in more than eighty countries
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15. SNOMED CT cont.
◼ SNOMED CT is definitely a clinical and a reference
terminology
➢ Not a classification
◼ January 2019 release
➢ ? concepts
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16. LOINC
◼ “The universal standard for identifying health measurements,
observations, and documents.”
◼ https://loinc.org/
◼ Latest version: 2.65 (2018-12-14) (89271 terms)
◼ What LOINC is:
➢ LOINC is a common language (set of identifiers, names, and codes)
for identifying health measurements, observations, and documents. If
you think of an observation as a "question" and the observation result
value as an "answer."
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17. LOINC – More details
◼ LOINC is definitely a clinical terminology
➢ Not a classification
◼ Is it a reference terminology?
➢ No, according to the SKMT definition
➢ LOINC does not provide a set of atomic level designations structured
to support representations of both simple and compositional concepts
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18. LOINC Hierarchy?
◼ Computable hierarchies exist in LOINC, but are not currently
exposed in a relational or semantic network format that
would be easy for a terminology server to consume. The
hierarchy can be graphically displayed by clicking on "Set
Hierarchy and Search Limits" tab in RELMA, component
hierarchy tab, then clicking on "+" sign next to items you are
interested in.
◼ However, the Multiaxial Hierarchy is part of the standard
LOINC distribution (one of the Accessory Files)
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19. LOINC Content
◼ Laboratory
➢ The laboratory portion of LOINC covers anything that you can test,
measure, or observe about a specimen. It contains the usual
categories of chemistry, hematology, serology, microbiology
(including parasitology and virology), toxicology; as well as categories
for cell counts, antibiotic susceptibilities, and more.
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20. LOINC Content
◼ Clinical
➢ We think of "clinical" as pretty much everything except lab. The
clinical portion of LOINC covers anything that you can test, measure,
or observe about a patient without removing that specimen from
them. LOINC has codes for observations like vital signs,
hemodynamics, intake/output, EKG, obstetric ultrasound, cardiac
echo, urologic imaging, gastroendoscopic procedures, pulmonary
ventilator management, radiology studies, clinical documents,
selected survey instruments (e.g. Glasgow Coma Score, PHQ-9
depression scale, CMS-required patient assessment instruments),
and other clinical observations.
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21. Overlap between SNOMED CT and LOINC
◼ There is general overlap with SNOMED across the entire
scope of LOINC
◼ But there are different modeling approaches and often
different levels of specificity and degree of detail (granularity)
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22. SNOMED CT and LOINC
◼ From LOINC:
➢ SNOMED is a large, comprehensive computerized clinical
terminology covering clinical data for diseases, clinical findings, and
procedures. In HL7 ORU messages, LOINC provides codes for the
question (OBR-4, OBX-3) while SNOMED provides codes for the
answers (OBX-5).
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23. SNOMED CT and LOINC
◼ From SNOMED:
➢ In 2013, IHTSDO and Regenstrief Institute Inc. signed a long-term
agreement to begin cooperative work linking their leading global
health care terminologies: Logical Observation Identifiers Names and
Codes, or LOINC, and SNOMED CT. This agreement has aimed to
improve safety, functionality and interoperability for the rapidly
growing number of clinicians who manage and exchange health data
with electronic medical records.
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24. SNOMED – LOINC Agreement Key Points
◼ LOINC parts and SNOMED CT concepts in the observables
model will be mapped to one another
◼ Existing SNOMED CT concepts that are subtypes of
Observable Entity or Evaluation Procedure will be mapped to
LOINC terms
◼ LOINC terms that are not already represented by SNOMED
CT concepts will be associated with post-coordinated
expressions
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25. SNOMED – LOINC Agreement Key Points
◼ Will not add new SNOMED CT “Observable Entity” and
“Evaluation Procedure” concepts, except when:
◼ A specific requirement has been formally submitted by two or
more IHTSDO members and the additional concept has
been modeled and reviewed in line with SNOMED CT
editorial guidelines (from LOINC terms only with permission)
◼ Or, a LOINC term cannot be sufficiently specified by a post-
coordinated expression based on the SNOMED CT Concept
Model and the additional concept meets editorial guidelines
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26. LOINC – Competitor or Cooperator?
◼ Actually, both
◼ SNOMED CT and LOINC generally peacefully co-exist
◼ And cooperate in specific areas (e.g. observables)
➢ To varying degrees over time
➢ Further work is on hold at the present time
◼ We’ll need to see how this continues to play out going
forward
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27. Practical information model considerations
◼ In Observations (V2, CDA, FHIR, others), with ‘code’ and
‘value’
➢ LOINC can represent the question
➢ SNOMED CT can provide the answer (when it’s a coded answer)
➢ But SNOMED CT can usually represent the question, too, depending
on specific needs and desires
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28. ICD-10
◼ International Classification of Diseases, 10th Revision
◼ Published by WHO
◼ ICD is the foundation for the identification of health trends
and statistics globally, and the international standard for
reporting diseases and health conditions. It is the diagnostic
classification standard for all clinical and research purposes.
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29. ICD-10
◼ ICD defines the universe of diseases, disorders, injuries and
other related health conditions, listed in a comprehensive,
hierarchical fashion that allows for:
➢ easy storage, retrieval and analysis of health information for
evidenced-based decision-making;
➢ sharing and comparing health information between hospitals, regions,
settings and countries; and
➢ data comparisons in the same location across different time periods.
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30. ICD-10 – More details
◼ ICD-10 is definitely a classification, per the SKMT definition
(and as further noted by SNOMED)
◼ Since SNOMED CT is a clinical and reference terminology
and ICD-10 is a classification, overlap in content isn’t an
issue
◼ They have different uses:
➢ ICD-10 primarily used for reporting, statistical analysis and
reimbursement
➢ SNOMED CT for detailed clinical coding
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31. SNOMED CT to ICD-10 mapping
◼ Purpose
➢ To provide a semi-automated coding of ICD-10 statistical
classification data from a clinical record which is clinically encoded in
SNOMED CT
➢ To aid in the development of ICD-10 classification codes from
SNOMED CT-encoded records for use in registries and diagnosis
groupers
➢ To serve as a SNOMED CT to ICD-10 map validated and sanctioned
by the WHO and SNOMED International and as a source for the
development of maps to ICD-10 extensions developed and
maintained by a member country
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32. SNOMED CT to ICD-10 mapping
◼ It Is Not
➢ A completely automated ICD-10 coding from a SNOMED CT source
➢ Support for social, cultural, ethical or financial constraints on ICD-10
coding required by members or other organizations
➢ A map that supports management of context beyond that found in the
coded record and ICD-10 conventions and rules as noted in this
document
➢ A map that optimizes or manipulates ICD-10 codes for reimbursement
purposes
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33. ICD-10 – Competitor or Cooperator?
◼ Neither, really
◼ Co-exist and work together independently
◼ Have different spheres of use
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34. Practical information model considerations
◼ Diagnoses in many systems are coded using ICD-10
➢ True for existing systems in Finland
◼ The terms frequently aren’t “clinician friendly”
◼ Levels of granularity aren’t appropriate or sufficient
◼ Terms have only a single parent – only can appear in one
place
◼ Best to use a clinical terminology, specifically SNOMED CT,
for coding diagnoses and related clinical data
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35. ICPC
◼ ICPC-2 classifies patient data and clinical activity in the
domains of General/Family Practice and primary care, taking
into account the frequency distribution of problems seen in
these domains. It allows classification of the patient’s reason
for encounter (RFE), the problems/diagnosis managed,
interventions, and the ordering of these data in an episode of
care structure
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36. ICPC
◼ It has a biaxial structure and consists of 17 chapters, each
divided into 7 components dealing with symptoms and
complaints (comp. 1), diagnostic, screening and preventive
procedures (comp. 2), medication, treatment and procedures
(comp. 3), test results (comp. 4), administrative (comp. 5),
referrals and other reasons for encounter (comp. 6) and
diseases (comp. 7).)
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37. ICPC
◼ It has a biaxial structure and consists of 17 chapters, each
divided into 7 components dealing with symptoms and
complaints (comp. 1), diagnostic, screening and preventive
procedures (comp. 2), medication, treatment and procedures
(comp. 3), test results (comp. 4), administrative (comp. 5),
referrals and other reasons for encounter (comp. 6) and
diseases (comp. 7).)
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38. ICPC – More details
◼ ICD-10 is definitely a classification, per the SKMT definition
◼ There is overlap in content with SNOMED CT where both
can be used
➢ Reason for encounter
➢ Diagnosis
➢ Interventions
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39. SNOMED CT to ICPC mapping
◼ SNOMED CT to ICPC-2 map provided through a
collaboration agreement between WONCA and SNOMED
International
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40. ICPC – Competitor or Cooperator?
◼ In some cases ICPC could be a competitor, in its areas of
use, but mostly not
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41. Practical information model considerations
◼ Reason for encounter is primary use for encoding in ICPC
◼ How much use of ICPC in Finland?
◼ A clinical terminology like SNOMED CT with more complete
and granular content and hierarchy is likely a better choice
when available
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42. Questions?
Rob Hausam
rob@hausamconsulting.com
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