2. http://ontologist.com 1/24 An ontology-based methodology for the migration of biomedical terminologies to the EHR Barry Smith and Werner Ceusters

3. http://ontologist.com 2/24 Current Orthodoxy: Concept-Based Coding

4. http://ontologist.com 3/24 The concept diabetes mellitus becomes ‘associated with a diabetic patient’ concept patient concept diabetes

5. http://ontologist.com 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

6. http://ontologist.com 5/24 The story of Jane Smith

7. http://ontologist.com 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

8. http://ontologist.com 7/24 A visit to the hospital City Health Centre Dr. Peters (City HC) Dr. Longley

9. http://ontologist.com 8/24 Diagnosis: a severe spiral fracture of the femur

10. http://ontologist.com 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

11. http://ontologist.com 10/24 557204/07/199026442006closed fracture of shaft of femur 557204/07/199081134009Fracture, closed, spiral 557212/07/199026442006closed fracture of shaft of femur 557212/07/19909001224Accident in public building (supermarket) 557204/07/199079001Essential hypertension 093924/12/1991255174002benign polyp of biliary tract 230921/03/199226442006closed fracture of shaft of femur 230921/03/19929001224Accident in public building (supermarket) 4780403/04/199358298795Other lesion on other specified region 557217/05/199379001Essential hypertension 29822/08/19932909872Closed fracture of radial head 29822/08/19939001224Accident in public building (supermarket) 557201/04/199726442006closed fracture of shaft of femur 557201/04/199779001Essential hypertension PtIDDateObsCodeNarrative 093920/12/1998255087006malignant 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 ?

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

13. http://ontologist.com 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,...

14. http://ontologist.com 13/24 The solution unique numerical IDs for all concrete individual entities relevant to the diagnosis and therapy of each patient

15. http://ontologist.com 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

16. http://ontologist.com 15/24 types / conceptsinstances / particulars scientific texts, dictionaries diaries, biographies, histories, journalism medical ontologies, terminologies clinical records

17. http://ontologist.com 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

18. http://ontologist.com 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

19. http://ontologist.com 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

20. http://ontologist.com 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

21. http://ontologist.com 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

22. http://ontologist.com 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

23. http://ontologist.com 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 http://ontology.buffalo.edu/referent- tracking