The BRIDG project: a technical report

Abstract

Objectives: The Biomedical Research Integrated Domain Group (BRIDG) project is a collaborative initiative between the National Cancer Institute (NCI), the Clinical Data Interchange Standards Consortium (CDISC), the Regulated Clinical Research Information Management Technical Committee (RCRIM TC) of Health Level 7 (HL7), and the Food and Drug Administration (FDA) to develop a model of the shared understanding of the semantics of clinical research.

Design: The BRIDG project is based on open-source collaborative principles and an implementation-independent, use-case driven approach to model development. In the BRIDG model, declarative and procedural knowledge are represented using the Unified Modeling Language (UML) class, activity and state diagrams.

Measurements: The BRIDG model currently contains harmonized semantics from four project use cases: the caXchange project and the patient study calendar project from caBIG; the standard data tabular model (SDTM) from CDISC; and the regulated products submission model (RPS) from HL7. Scalable harmonization processes have been developed to expand the model with content from additional use cases.

Results: The first official release of the BRIDG model was published in June 2007. Use of the BRIDG model by the NCI has supported the rapid development of semantic interoperability across applications within the caBIG program.

Conclusions: The BRIDG project has brought together different standards communities to clarify the semantics of clinical research across pharmaceutical, regulatory, and research organizations. Currently, the NCI uses the BRIDG model to support interoperable application development in the caBIG, and CDISC and HL7 are using the BRIDG model to support standards development.

Figure 1

Type I semantic mismatch and the semiotic triangle. The notion of a semiotic triangle is a concept from linguistics. A symbol or name is associated with an underlying concept that individuals have within their minds. Confusion and difficulty with communication typically occur when the same symbol is applied by different people to different concepts. In this diagram, the same symbol “protocol” is used by two different individuals to refer to two different concepts. Concept 1 refers to a protocol as a policy document, while concept 2 describes the protocol as a study. Conceptually, it is not possible to enroll a patient into a document. The process of harmonization attempts to make explicit the semiotic triangles and forces domain experts to be explicit about the definitions that they apply to names within the clinical trials domain.

Figure 2

Type II Semantics mismatches. In this diagram two different symbols (“protocol” and “clinical trial”) both point to the same concept but use different terms to describe that concept.

Figure 4

Capturing the procedural semantics using activity diagrams. This is an implementation specific diagram of the organizational processes for managing adverse events, and illustrates how data (declarative semantics) can be associated with particular activities (procedural semantics) used in the conduct of a clinical trial. This particular diagram describes how adverse events can trigger schedule changes for a patient in the data that is required to evaluate those changes.