Implementation of a query interface for a generic record server

This paper presents work to define a representation for clinical research queries that can be used for the design of generic interfaces to electronic healthcare record (EHR) systems. Given the increasing prevalence of EHR systems, with the potential to accumulate life-long health records, opportunities exist to analyse and mine these for new knowledge. This potential is presently limited by many factors, one of which is the challenge of extracting information from them in order to execute a research query.

There is limited pre-existing work on the generic specification of clinical queries. Sets of example queries were obtained from published studies and clinician reference groups. These were re-represented as structured logical expressions, from which a generalisable pattern (information model) was inferred. An iterative design and implementation approach was then pursued to refine the model and evaluate it.

This paper presents a set of requirements for the generic representation of clinical research queries, and an information model to represent any arbitrary such query. A middleware component was implemented as an interface to an existing system that holds 20,000 anonymised cancer EHRs in order to validate the model. This component was interfaced in turn to a query design and results presentation tool developed by the Open University, to permit end user demonstrations and feedback as part of the evaluation.

Although it is difficult to separate cleanly the evaluation of a theoretical model from its implementation, the empirical evaluation of the query-execution interface revealed that clinical queries of the kinds studied could all be represented and executed successfully. However, performance was a problem and this paper outlines some of the challenges faced in building generic components to handle specialised data structures on a large scale. The limitations of this work are also discussed. The work complements many years of European research and standardisation on the interoperable communication of electronic health records, by proposing a way in which one or more EHR systems might be queried in a standardised way.