title: Competing interpretations of disorder codes in SNOMED CT and ICD.
abstract: Under ontological scrutiny we have identified two competing interpretations of disorder concepts in SNOMED. Should codes be interpreted as representing pathological conditions themselves or the situations in which a patient has those conditions? This difference has significant implications for the proposed harmonization between SNOMED CT and the new ICD-11 disease classification and indeed for any systematic review of the correctness of the SNOMED CT hierarchies. Conditions themselves are distinct, whereas in any given situation a patient may have more than one condition. In such cases, SNOMED codes that represent combinations of conditions - which can be regarded as "additive" - are evidence for interpreting the codes as referring to situations. There are clearly some such codes. We conducted a survey to determine the extent of this phenomenon. Three criteria were used - analysis of the SNOMED CT fully specified name, the corresponding logical definition, and the children of the concept under scrutiny. All three showed that at least 11% of concepts met our criteria for representing situations rather than conditions, with a satisfactory inter-rater reliability for the first two. We, therefore, conclude that if a uniform interpretation of SNOMED disorder codes is desired, they should be interpreted as representing situations.
authors.affiliation: Institute for Medical Informatics, Statistics and Documentation, Med. University Graz, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schulz
authors.forename: Alan
authors.initials: A
authors.lastname: Rector
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Rodrigues
authors.forename: Kent
authors.initials: K
authors.lastname: Spackman
mesh_terms: D002648:Child; D004194:Disease / Q000145:classification*; D006801:Humans; D038801:International Classification of Diseases; D010865:Pilot Projects; D011885:Radius Fractures / Q000145:classification; D057386:Search Engine; D039061:Systematized Nomenclature of Medicine; D014458:Ulna Fractures / Q000145:classification