ECO R European Centre for Ontological Research Referent Tracking in Electronic Health Records MIE 2005, Geneva Dr. W. Ceusters European Centre for Ontological Research Saarland University, Saarbrücken - Germany Barry Smith Institute for Ontology and Medical Information Science Saarland University, Saarbrücken - Germany

ECO R European Centre for Ontological Research Current mainstream thinking data information knowledge wisdom - representation (- representation) Questions not often enough asked: What part of our data corresponds with something out there in reality ? What part of reality is not captured by our data, but should because it is relevant ? Reality What is there on the side of the patient

ECO R European Centre for Ontological Research The story of Jane Smith an old case, well known in the literature...

ECO R European Centre for Ontological Research Jane’s favourite supermarket July 4th, 1990: Jane goes shopping: The freezer section of Jane’s favourite supermarket The only available warning sign used outside A very suspiciously shaped upper leg

ECO R European Centre for Ontological Research A visit to the hospital City Health Centre Dr. Peters (City HC) Dr. Longley

ECO R European Centre for Ontological Research Diagnosis: a severe spiral fracture of the femur

ECO R European Centre for Ontological Research CityHC’s representation formalism (for statements in records) Rector AL, Nowlan WA, Kay S, Goble CA, Howkins TJ. A framework for modelling the electronic medical record. Methods Inf Med Apr;32(2): Categories: “ represent concepts and are analogous to classes in other formalisms ” Individuals: “ concrete instances of categories which persist in space and time ” Occurrences: “ are specific occurrences of individuals and must be situated in space and time. The most important group of occurrences are observations — i.e. agents ’ observations of individuals. ”

ECO R European Centre for Ontological Research /07/ closed fracture of shaft of femur /07/ Fracture, closed, spiral /07/ closed fracture of shaft of femur /07/ Accident in public building (supermarket) /07/ Essential hypertension /12/ benign polyp of biliary tract /03/ closed fracture of shaft of femur /03/ Accident in public building (supermarket) /04/ Other lesion on other specified region /05/ Essential hypertension 29822/08/ Closed fracture of radial head 29822/08/ Accident in public building (supermarket) /04/ closed fracture of shaft of femur /04/ Essential hypertension PtIDDateObsCodeNarrative /12/ malignant polyp of biliary tract Same patient, same hypertension code: Same (numerically identical) hypertension ? Different patients, same fracture codes: Same (numerically identical) fracture ? Same patient, different dates, same fracture codes: same (numerically identical) fracture ? Same patient, same date, 2 different fracture codes: same (numerically identical) fracture ? Same patient, different dates, Different codes. Same (numerically identical) polyp ? Registration through generic names But, there are some problems... Different patients. Same supermarket? Maybe the same (irrelevant ?) freezer section ? Or different supermarkets, but always in the freezer sections ?

ECO R European Centre for Ontological Research Main problem areas for CityHC’s EHR Statements refer only very implicitly to the concrete entities about which they give information. Idiosyncracies of concept-based terminologies – tell us only that some instance of the class the codes refer to, is refered to in the statement, but not what instance precisely. – Are usually confused about classes and individuals. “Country” and “Belgium”. Mixing up the act of observation and the thing observed. Mixing up statements and the entities these statements refer to.

ECO R European Centre for Ontological Research Consequences Very difficult to: – Count the number of (numerically) different diseases Bad statistics on incidence, prevalence,... Bad basis for health cost containment – Relate (numerically same or different) causal factors to disorders: – Dangerous public places (specific work floors, swimming pools), – dogs with rabies, – HIV contaminated blood from donors, – food from unhygienic source,... Hampers prevention –...

ECO R European Centre for Ontological Research Proposed solution: Referent Tracking Purpose: – explicit reference to the concrete individual entities relevant to the accurate description of each patient’s condition, therapies, outcomes,... Method: – Introduce an Instance Unique Identifier (IUI) for each relevant individual (= particular, = instance). – Distinguish between IUI assignment: for instances that do exist IUI reservation: for entities expected to come into existence in the future

ECO R European Centre for Ontological Research Ontology ‘Ontology’: the study of being as a science ‘An ontology’ is a representation of some pre- existing domain of reality which – (1) reflects the properties of the objects within its domain in such a way that there obtains a systematic correlation between reality and the representation itself, – (2) is intelligible to a domain expert – (3) is formalized in a way that allows it to support automatic information processing ‘ontological’ (as adjective): – Within an ontology. – Derived by applying the methodology of ontology –...

ECO R European Centre for Ontological Research An ontological analysis continuants City HC The freezer section of Jane’s favourite supermarket Jane’s left femur Jane’s left femur fracture Jane Smith Dr. Peters Jane’s left femur Jane’s fracture’s image Dr. Longley City HC’s EHR system t Jane’s falling Jane’s femur breaking Dr. Peter’s examination of Jane’s fracture Dr. Peter’s ordering of an X-ray Shooting the pictures of Jane’s leg occurrents Jane’s fracture’s healing Dr. Peter’s diagnosis making Jane dies Freezer section dismantled Dr. Longley’s examination of Jane’ s fracture Jane’s fracture as seen by Dr. Peters Jane’s fracture as seen by Dr. Longley Instances of Jane’s fracture Universals EHR system HC Freezer section Person Femur Fracture Image

ECO R European Centre for Ontological Research Ontological recategorisation CityHCDr. Peters Jane Smith Jane Smith’s Fracture Of Femur Fracture Of Femur Severe Spiral City HC exists on 4th July 1990 Dr. Peters located at City HC on 4th July 1990 Jane Smith’s consultation with Dr. Peters at City HC on 4th July 1990 Dr. Peters’ assessment of Jane Smith’s fracture of femur at City HC on 4th July 1990 Jane Smith’s Fracture Of Femur’s severity Jane Smith’s Fracture Of Femur’s shape

ECO R European Centre for Ontological Research Essentials of Referent Tracking Generation of universally unique identifiers; deciding what particulars should receive a IUI; finding out whether or not a particular has already been assigned a IUI (each particular should receive maximally one IUI); using IUIs in the EHR, i.e. issues concerning the syntax and semantics of statements containing IUIs; determining the truth values of statements in which IUIs are used; correcting errors in the assignment of IUIs.

ECO R European Centre for Ontological Research IUI assignment = an act carried out by the first ‘cognitive agent’ feeling the need to acknowledge the existence of a particular it has information about by labelling it with a UUID. ‘cognitive agent’: – A person; – An organisation; – A device or software agent, e.g. Bank note printer, Image analysis software.

ECO R European Centre for Ontological Research Criteria for IUI assignment (1) 1. The particular’s existence must be determined: – Easy for persons in front of you, body parts,... – Easy for ‘planned acts’: they do not exist before the plan is executed ! Only the plan exists and possibly the statements made about the future execution of the plan – More difficult: subjective symptoms But the statements the patient makes about them do exist ! – However: no need to know what the particular exactly is, i.e. which universal it instantiates No need to be able to point to it precisely – One bee out of a particular swarm that stung the patient, one pain out of a series of pain attacks that made the patient worried – But: this is not a matter of choice, not ‘any’ out of...

ECO R European Centre for Ontological Research Criteria for IUI assignment (2) 2. The particular’s existence ‘may not already have been determined as the existence of something else’: Morning star and evening star Himalaya Multiple sclerosis 3. May not have already been assigned a IUI. 4. It must be relevant to do so: Personal decision, (scientific) community guideline,... Possibilities offered by the EHR system If a IUI has been assigned by somebody, everybody else making statements about the particular should use it

ECO R European Centre for Ontological Research Representation in the EHR Relevant particulars referred to using IUIs Relationships that obtain between particulars at time t expressed using relations from an ontology (type OBO) Statements describing for each particular, at time t: – Of what universal from an ontology it is an instance of – AND/OR (if one insists): – By means of what concept from a concept-based system it can sensibly be described CityHCDr. Peters Jane Smith Jane Smith’s Fracture Of Femur Fracture Of Femur Severe Spiral Jane Smith’s consultation with Dr. Peters at City HC on 4th July 1990 Dr. Peters’ assessment of Jane Smith’s fracture of femur at City HC on 4th July 1990 Jane Smith’s Fracture Of Femur’s severity Jane Smith’s Fracture Of Femur’s shape 4th July 1990 particulars

ECO R European Centre for Ontological Research Pragmatics of IUIs in EHRs IUI assignment requires an additional effort In principle no difference qua (or just a little bit more) effort compared to using directly codes from concept-based systems – A search for concept-codes is replaced by a search for the appropriate IUI using exactly the same mechanisms Browsing Code-finder software Auto-coding software (CLEF NLP software Andrea Setzer) – With that IUI comes a wealth of already registered information – If for the same patient different IUIs apply, the user must make the decision which one is the one under scrutiny, or whether it is again a new instance A transfert or reference mechanism makes the statements visible through the RTDB

ECO R European Centre for Ontological Research Advantage: better reality representation /07/ closed fracture of shaft of femur /07/ Fracture, closed, spiral /07/ closed fracture of shaft of femur /07/ Accident in public building (supermarket) /07/ Essential hypertension /12/ benign polyp of biliary tract /03/ closed fracture of shaft of femur /03/ Accident in public building (supermarket) /04/ Other lesion on other specified region /05/ Essential hypertension 29822/08/ Closed fracture of radial head 29822/08/ Accident in public building (supermarket) /04/ closed fracture of shaft of femur /04/ Essential hypertension PtIDDateObsCodeNarrative /12/ malignant polyp of biliary tract IUI-001 IUI-003 IUI-004 IUI-005 IUI-007 IUI-002 IUI-012

ECO R European Centre for Ontological Research Other Advantages mapping as by-product of tracking – Descriptions about the same particular using different ontologies/concept-based systems Quality control of ontologies and concept- based systems – Systematic “inconsistent” descriptions in or cross terminologies may indicate poor definition of the respective terms

ECO R European Centre for Ontological Research Conclusion Referent tracking can solve a number of problems in an elegant way. Existing (or emerging) technologies can be used for the implementation. Old technologies (concept-based systems) can play an interesting, but different role. Big Brother feeling is to be expected but with adequate measures easy to fight. The proof of the pudding is in the eating – Pilote is going to be set up