Transforming nursing documentation data into the Observational Medical Outcomes Partners common data model

Electronic health records (EHRs) provide clinical evidence for observational studies. Of these, nursing documentation data reflect patients' problems or situations and nursing services that are not available from other data sources; however, they have not been actively utilized in research owing to their low quality of documentation.

The objectives of this study were to 1) transform nursing documentation data into the Observational Medical Outcomes Partnership (OMOP) common data model (CDM) format and 2) generate a cohort of inpatients with nausea by utilizing transformed nursing documentation data to present the effectiveness of standardization.

A total of 4006 unique nursing statements used in nursing documentation were extracted from the EHRs of a tertiary general hospital in a South Korean metropolitan area. They were standardized primarily using Systematized Nomenclature Of Medicine Clinical Terms (SNOMED CT), one of the OMOP vocabularies, according to the mapping principles and guidelines. After converting the data into the OMOP CDM format, a cohort of inpatients with nausea was generated by utilizing nursing statements mapped into the "nausea," "nausea care," and "nausea care education" concepts. We then compared the size and demographic characteristics of the cohort with those of a cohort generated based on the diagnosis and chief complaint of nausea.

Of the 4006 unique nursing statements, 98.9% were mapped to SNOMED CT concepts. In total, almost 200 million nursing statements from 2,537,310 cases were standardized and converted into OMOP CDM data. They were stored in the observation, procedure_occurrence, and measurement tables, according to their respective mapping domains. Of the hospitalization cases from May 2003 to December 2022, the cohort generated using standardized nursing statements related to nausea consisted of 214,830 cases, whereas the cohort generated using diagnosis and chief complaints consisted of 12,381 cases.

To the best of our knowledge, this is the first study to convert nursing documentation data into the OMOP CDM format. As a follow-up study, it will be necessary to expand the standardization methods and principles established in this study to other institutions participating in the OMOP CDM project.