The “Common Ontology”
between ICD 11 and SNOMED CT
medical plausibility vs. ontological soundness
Stefan Schulz
Medical University of Graz
[email protected]
http://purl.org/steschu
ICD-11 – SNOMED CT harmonization
• Background:
– ICD: Classification maintained by WHO, currently under revision 
ICD-11
– SNOMED CT: Ontology-based clinical terminology maintained by
IHTSDO (International Health Terminology Standards Development
Organisation)
• Large content overlap between ICD and SNOMED CT
disorder / findings hierarchy
• Joint Advisory Group (WHO and IHTSDO), based on
institutional agreement:
– Synergistic and not antagonistic terminology development
– Jointly develop a common ontological basis for both
ICD-11 and SNOMED CT
– Maximum of interoperability between ICD and SNOMED coded data
ICD-11 Foundation
Common
SNOMED – ICD11 Ontology
Subset of
SNOMED CT
ICD-11
Foundation Ontology
Foundatio
Common
SNOMED –
ICD-11
Ontology
Subset of ICD-11
ICD-11
Content Model
Content
Model
Schema
value sets
External
External
External
External
sources
sources
links
Sources
Query Library
Linearization
A A
Linearization set
(nested)
Linearization B
(un-nested)
Content
Model
Contents
Linearization C
(un-nested)
Inventory of
clinicians‘
language:
words, terms,
phrases
Categorization and
formal description of
domain entities:
clinical situations,
information entities,
taxonomies, partonomies
Purpose-specific
reporting units:
billing,
health statistics
SNOMED CT
ICD-11
Vocabulary
Inventory of
clinicians‘
language:
words, terms,
phrases
Categorization and
formal description of
domain entities:
clinical situations,
information entities,
taxonomies, partonomies
SNOMED CT
Ontology
Classification
ICD-11
Purpose-specific
reporting units:
billing,
health statistics,
research,…
SNOMED CT
ICD-11
Vocabulary
Inventory of
clinicians‘
language:
words, terms,
phrases
Desiderata:
pragmatic
orderings for
specific purposes
Classification
Purpose-specific
reporting units:
billing,
health statistics,
research,…
Desiderata: contextindependent, precise
categorizations
ICD-11
Desiderata: Readyto-use terms, oneclick encoding of
complex statements
Categorization and
formal description of
domain entities:
clinical situations,
information entities,
taxonomies, partonomies
SNOMED CT
Ontology
Fracture of
Radius
Fracture of
Ulna
Fracture of radius
and ulna
Fracture of forearm
Fracture of shaft of ulna
Fracture of shaft of radius
Fracture of shafts of
both ulna and radius
SNOMED CT Findings/Disorders
and WHO – IHTSDO
Common Ontology
Formal taxonomies of
clinical situations
(life periods in which one or more
clinical conditions are present)
ICD-11
Linearizations
Hierarchical orderings of
reporting units
into disjoint “classes”
Multiple hierarchies:
Mitral valve
disease
Rheumatic
heart disease
Rheumatic mitral
valve stenosis
Single hierarchies + exclusions
Mitral valve
disease
Rheumatic
heart disease
Excl: Heart valve
diseases
Rheumatic mitral
valve stenosis
SNOMED CT Findings/Disorders
and WHO – IHTSDO
Common Ontology
Formal taxonomies of
clinical situations
(life periods in which one or more
clinical conditions are present)
ICD-11
Linearizations
Hierarchical orderings of
reporting units
into disjoint “classes”
Strict taxonomic relations
Fibrosis of the
skin
Disorder of skin
of lower limb
Lipodermatosclerosis
SNOMED CT Findings/Disorders
and WHO – IHTSDO
Common Ontology
Formal taxonomies of
clinical situations
(life periods in which one or more
clinical conditions are present)
Approximate taxonomies
Chronic peripheral
venous insufficiency
Lipodermatosclerosis
ICD-11
Linearizations
Hierarchical orderings of
reporting units
into disjoint “classes”
Separation Ontology/
Epistemology
Tuberculosis
Confirmed
present
Tuberculosis of
respiratory
system
Fusion Ontology/
Epistemology
Tuberculosis of the
respiratory system
Respiratory tuberculosis,
confirmed
Respiratory tuberculosis,
suspected
SNOMED CT Findings/Disorders
and WHO – IHTSDO
Common Ontology
Formal taxonomies of
clinical situations
(life periods in which one or more
clinical conditions are present)
ICD-11
Linearizations
Hierarchical orderings of
reporting units
into disjoint “classes”
SNOMED CT Findings/Disorders
and WHO – IHTSDO
Common Ontology
B
A
C
Mapping as Querying
Query mechanism, e.g.
X = select A minus select B
Y = select A and B
Z = select A and (rel C)
…
Formal taxonomies of
clinical situations
(life periods in which one or more
clinical conditions are present)
ICD-11
Linearizations
Hierarchical orderings of
reporting units
into disjoint “classes”
Y
X
Z
ICD-11 Foundation
Common
SNOMED – ICD11 Ontology
Subset of
SNOMED CT
ICD-11
Foundation Ontology
Foundatio
Common
SNOMED –
ICD-11
Ontology
Subset of ICD-11
ICD-11
Content Model
Content
Model
Schema
value sets
External
External
External
External
sources
sources
links
Sources
Query Library
Linearization
A A
Linearization set
(nested)
Linearization B
(un-nested)
Content
Model
Contents
Linearization C
(un-nested)