A three-tier clinical information systems design model.

Modern health care institutions are often multi-site organisations that implement heterogeneous information management systems interacting with distributed databases. Advances in treatment modality/technology and rapidly changing information technology create increasing demand for changes/redevelopment of many health information applications. These features spawn the need for solutions to (a) guarantee data exchange across different types of applications and database management systems, and (b) reduce the costs of systems development and modification. This paper explores the concept of 'middleware services' as a solution to achieve these goals. It reports on the successful application of a component-based 3-tier system architecture to develop a computerised clinical pathways management system. The implementation experience confirms a number of significant benefits of the 3-tier structure including, reusability, flexibility, significant reduction in costs and efforts of systems development, and provision of easy, open migration pathway for future change of technology and system redevelopment.