1/24 An ontology-based methodology for the migration of biomedical terminologies to the EHR Barry Smith and Werner Ceusters

2/24 Current Orthodoxy: Concept-Based Coding

3/24 The concept diabetes mellitus becomes ‘associated with a diabetic patient’ concept patient concept diabetes

4/24 ? The concept diabetes mellitus becomes ‘associated with a diabetic patient’ ? concept patient concept diabetes what it is on the side of the patient

5/24 The story of Jane Smith

6/24 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

7/24 A visit to the hospital City Health Centre Dr. Peters (City HC) Dr. Longley

8/24 Diagnosis: a severe spiral fracture of the femur

9/24 Standard EHRs Specific codes for: patients, physicians, times, places, sometimes to X-ray images General codes for everything else The record tells us that there is some instance of the class the code refers to

10/ /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 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 ? Problems Different patients. Same supermarket? Same freezer section? Same patient, different dates, Different codes. Same (numerically identical) polyp ?

11/24 Difficult to: count the number of (numerically) different diseases (bad statistics on incidence, prevalence, cost...)

12/24 Difficult to: relate (numerically the same or different) causal factors to disorders: Dangerous public places (swimming pools) HIV contaminated blood food from unhygienic source,...

13/24 The solution unique numerical IDs for all concrete individual entities relevant to the diagnosis and therapy of each patient

14/24 Referent tracking already used as a matter of course for bank and credit card transactions Fedex / UPS parcels cargo conveyor belt manufacturing mp3 files (for Digital Rights Management) archeological specimens

15/24 types / conceptsinstances / particulars scientific texts, dictionaries diaries, biographies, histories, journalism medical ontologies, terminologies clinical records

16/24 types rabbit, headache, human being, salute, death Mary’s rabbit, my current headache, me, Rumsfeld’s salute at 4pm on 6/22/04, Reagan’s death instances

17/24 Referent Tracking Method: introduce an Instance Unique Identifier (IUI) for each relevant individual entity Outcome: An ever growing map of clinical cases, and of their interrelations to other clinical cases

18/24 Services –IUI generator –IUI assignment (facility now in openEHR) –IUI repository –Referent Tracking Database (RTDB): statements relating instances to instances and types software now available will be tested in a clinical setting

19/24 Conclusion 1/4 Referent tracking can solve a number of problems in an elegant way Existing coding systems and technologies can be used for the implementation The use of Health Card technology will make the assignment of IUIs very easy to implement Use of randomly assigned alphanumeric IDs can also bring data security advantages

20/24 Conclusion 2/4 because the same patient often attends different hospitals using different coding systems the use of common IUI repositories will gradually lead to automatic mappings between terminologies

21/24 Conclusion 3/4 as IUIs come to be associated with a plurality of codes from different coding systems we can run statistical tests to find outliers – codes which were misapplied; or ill- defined or to test and enhance rules for reasoning postulated by coding systems such as SNOMED-CT

22/24 Conclusion 4/4 Over time, the IUI repository will come to serve as a benchmark of correctness for coding systems allowing automatic step-by-step improvements tracking