Harmonization process for the identification of medical events in eight European healthcare databases: the experience from the EU-ADR project by Paul Avillach, et. al. (J Am Med Inform Assoc doi:10.1136/amiajnl-2012-000933)
Abstract
Objective Data from electronic healthcare records (EHR) can be used to monitor drug safety, but in order to compare and pool data from different EHR databases, the extraction of potential adverse events must be harmonized. In this paper, we describe the procedure used for harmonizing the extraction from eight European EHR databases of five events of interest deemed to be important in pharmacovigilance: acute myocardial infarction (AMI); acute renal failure (ARF); anaphylactic shock (AS); bullous eruption (BE); and rhabdomyolysis (RHABD).
Design The participating databases comprise general practitioners’ medical records and claims for hospitalization and other healthcare services. Clinical information is collected using four different disease terminologies and free text in two different languages. The Unified Medical Language System was used to identify concepts and corresponding codes in each terminology. A common database model was used to share and pool data and verify the semantic basis of the event extraction queries. Feedback from the database holders was obtained at various stages to refine the extraction queries.
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Conclusions The iterative harmonization process enabled a more homogeneous identification of events across differently structured databases using different coding based algorithms. This workflow can facilitate transparent and reproducible event extractions and understanding of differences between databases.
Not to be overly critical but the one thing left out of the abstract was some hint about the “…procedure used for harmonizing the extraction…” which interests me.
The workflow diagram from figure 2 is worth transposing into HTML markup:
- Event definition
- Choice of the event
- Event Definition Form (EDF) containing the medical definition and diagnostic criteria for the event
- Concepts selection and projection into the terminologies
- Search for Unified Medical Language System (UMLS) concepts corresponding to the medical definition as reported in the EDF
- Projection of UMLS concepts into the different terminologies used in the participating databases
- Publication on the project’s forum of the first list of UMLS concepts and corresponding codes and terms for each terminology
- Revision of concepts and related terms
- Feedback from database holders about the list of concepts with corresponding codes and related terms that they have previously used to identify the event of interest
- Report on literature review on search criteria being used in previous observational studies that explored the event of interest
- Text mining in database to identify potentially missing codes through the identification of terms associated with the event in databases
- Conference call for finalizing the list of concepts
- Search for new UMLS concepts from the proposed terms
- Final list of UMLS concepts and related codes posted on the forum
- Translation of concepts and coding algorithms into queries
- Queries in each database were built using:
- the common data model;
- the concept projection into different terminologies; and
- the chosen algorithms for event definition
- Query Analysis
- Database holders extract data on the event of interest using codes and free text from pre-defined concepts and with database-specific refinement strategies
- Database holders calculate incidence rates and comparisons are made among databases
- Database holders compare search queries via the forum
At least for non-members, the EU-ADR website does not appear to offer access to the UMLS concepts and related codes mapping. That mapping could be used to increase accessibility to any database using those codes.