gms | German Medical Science

Improving efficiency and quality for health systems including social care, prevention, homecare and lifestyle in an aging society with increasing demands for innovative and better health services can only be met by comprehensively integrating all services including medical, social, community, and public health. Integrated public health services empower the health system by providing more complete information to improve diagnosis and treatment, e.g. epidemiological information, public health guidelines and protocols, promotion and prevention programs, alerts for public health services, etc., also reducing the effort in mandatory notification processes.

Accomplishing health information systems integration is neither organizationally nor technically simple. Clinical and public health systems are related to different domains, each one describing different business process, concepts, and rules. In order to deal with the challenge of facilitating effective service integration (service interoperability) between existent/future clinical and public health information systems, the information systems development process has to be centered in a service-oriented architecture.

In the paper, a health IT service for the reporting of public health events is designed following a model-driven development process. The service is presented in the context of an integrated EHR infrastructure.

Information systems and components are in the best cases purchased - requiring an adaptation to the specific business requirements and further integration to existent systems - or in-house developed by software development teams. Model-driven development (MDD) is the state of the art development process when services/components reusability, interoperability, portability, scalability and flexibility are required.

The Object Management Group (OMG) formalizes the MDD approach offering standards such as the model driven architecture (MDA), the unified modeling language (UML), the XML metadata interchange (XMI), etc. MDA, however, is mainly restricted to technological aspects of information systems architecture centered in platform-independent and platform specific models (PIM/PSM). The business architecture, although declared in the MDA computational-independent models (CIM), is not extensively covered in the MDA specification.

The service-oriented architecture (SOA) fills the MDA gap describing a modern, distributed system architecture, starting from the description of an enterprise business process. SOA is not a development process, however. It is just an architectural style that packages software resources as services, which are well defined, self-contained modules that provide standard business functionality and are independent of the state or context of other services [Ref. 1].

The Health Information Systems Development Framework (HIS-DF) is a development methodology for the development of semantically interoperable health information systems and components [Ref. 2]. HIS-DF addresses the complexity of health IT services development by defining a comprehensive development process which separates the different perspectives of a system architecture (e.g. business, computational and technology) and describes configurable method components and processes for HIS development including activities, roles, artifacts and guidelines. The framework facilitates the adoption of MDD and SOA, being based on UML models which separates and enables the transfer from PIM to PSM. Also the use of domain-specific knowledge is promoted by profiling health care standards such us HL7 information models [Ref. 3].

Based on the HIS-DF, the analysis, design and implementation of a Public Health Reporting Service has been completed. The Public Health Reporting service is intended to support the ongoing and systematic notification of events (cases) susceptible of public health reporting from clinical care facilities (e.g. hospitals, clinics, private consultations) to local, regional, or national public health offices.

Figure 1 [Fig. 1] describes the Public Health Reporting service’s main interfaces and a sample interaction diagram. Two interfaces have been defined, one for receiving information about a public health event (IPublicHealthReportingReceiveCase) and the other to receive requests for creating a consolidated report of events (IPublicHealthReportingCreateReport). The sequence diagram represents a clinical system sending messages containing information about a suspected case of a communicable disease occurrence. The Public Health Reporting service confirms that the cases haven’t been reported before, receiving then a message asking for a case entry creation. The interfaces are defined based on HL7 v3 specifications.

The service can be implemented using any software technology and supported at any platform. Using the MDD capabilities of the Rational Software Architect IDE, the interfaces in the UML component diagram where automatically transformed into WSDL (web service description language) interfaces. Afterwards, following a bottom-up approach, the internal behavior of the service was implemented as Enterprise JavaBeans (EJB) using UML to EJB transformations.

The service can be integrated into a service-oriented healthcare network infrastructure as shown in Figure 2 [Fig. 2]. The infrastructure encompasses common services such as service registry, security, privacy, terminology; business services such as EHR, personal health records, public health services, and legacy systems including laboratory, pharmacy, electronic medical record systems, etc. All services are integrated using an enterprise bus service infrastructure.

The Public Health Reporting service (black colored component) can be “consumed” by public health services, and also interacts with legacy systems such as a laboratory systems or EMRs, to provide different business functionalities. Also interoperability with common services is feasible.

Based on a model-driven methodology, and supported through a service-oriented architecture, a Health IT service for the notification of public health events has been analyzed, designed and implemented. The service deployment has been exemplified in the context for an integrated EHR Infrastructure.

The work was financially supported by the German Academic Exchange Service and Cauca University.