Interoperability and the EHR: Do you wanna make a SNOWMED?

The core of interoperability in the context of electronic health records is to ensure the sender and recipient of any health related information can read the data in the same manner, and also send and receive the information clearly across various infrastructures². The quest for interoperability initiated the efforts to standardize medical information, which led to the formalization of an Electronic Health Record (EHR).

Traditional health care models had been based around individual visits, and largely contained in isolated paper charts or unique electronic record systems under the health care provider’s authority. These records were normally not seen by the patient and could vary in structure from provider to provider, with safety being the responsibility of the individual at the time of treatment. In a newer patient centered model of healthcare, the continuous relationship with the patient and all treatments from all providers is emphasized, with visibility of the records and control granted to the patients and sharing of treatment information available to other health care providers². The early efforts of recording health information were not scalable for a growing population. The interoperability of the electronic health record relies on standardized ways to store and transfer the information, and this escalated the development of the problem oriented medical record format and the standardization of medical terms.

In the past, the documentation of health information varied between health care organizations, and paper and electronic systems. The terminology itself was known and standard, but the means of coding, searching, and comparing was not based on a formal structure the way chemicals and other scientific data had been. A system was needed so that information could be recorded in a way that is universally understood, not only by health care and related individuals but by a variety of computer systems that would act upon health data. The Systematized Nomenclature of Medicine-Clinical Terms, or SNOWMED CT came about to address the need to have predictable values arranged in a hierarchy in order to classify and document medical treatment. SNOWMED CT follows the principles that the data from the past needs to be usable in the future, and the data quality directly correlates to patient care options that are available to EHR users².

SNOWMED incorporates identifiers that make up a value set, and within these contain the relationships and descriptions.  The general outline is a top level of case classifications, a middle level to track and evaluate the clinical activity, and a base level used in the care setting.  This allows for indexing and searching not only for the point of care and exact clinical documentation, but for public health research and disease surveillance².

The SNOMED CT is the evolved comprehensive standard for healthcare terminology and has been adopted into the EHR. The ICD family of diagnosis descriptions and sub classifications is an example of how SNOWMED is applied to medical records. A new application is the anticipated adoption of the ICD-10 diagnosis coding and classification system, which has a hierarchy of conditions and specific rules to drill down to define specific conditions.

References:

1 Atherton, J (2011).  Development of the Electronic Health Record. American Medical Association Journal of Ethics. March 2011, Volume 13, Number 3: 186-189.  Retrieved from: http://journalofethics.ama-assn.org/2011/03/mhst1-1103.html or http://journalofethics.ama-assn.org/2011/03/pdf/mhst1-1103.pdf

2 Benson, T. (2012). Principles of Health Interoperability HL7 and SNOMED. Springer London. ISBN: 978-1-4471-2800-7 (Print) 978-1-4471-2801-4 (Online)

3 HealthIT.gov (2013). Implementing Consolidated-Clinical Document Architecture (C-CDA) for Meaningful Use Stage 2 .Clinical Document Architecture Overview.  Retrieved 4/6/15 from http://www.healthit.gov/sites/default/files/c-cda_and_meaningfulusecertification.pdf

4 Health Level 7 (2015). HL7/ASTM Implementation Guide for CDA R2 Continuity of Care document, Release 1. Health Level Seven International. Retrieve 2/3/15 from: http://www.hl7.org/implement/standards/product_brief.cfm?product_id=6