Simplifying the exchange of complex patient records

The University of St. Gallen is carrying out an important Web project as part of the Swiss long-term HIV study SHCS. Using XML technology, the university is integrating patient information from a variety of data sources for the first time in an XML database, which will subsequently also be accessible on the intranet. The aim of bringing together all the existing medical data is to improve the medical care provided to HIV patients. At the same time, extremely important research information is made available.

No field of activity will remain untouched by the effects of the information age; the critical issue is whether these challenges are viewed as risks or opportunities. In the health care system, in particular, the use of the latest information technology opens up new ways of storing, querying and distributing medical information. The Swiss HIV Cohort Study (SHCS) is the best example of this. Initially it was financed by the Swiss Bundesamt für Gesundheit (Federal Health Agency), but it is now funded by the Swiss National Science Foundation.

The long-term study of HIV patients in Switzerland started in 1988 and analyzed the development and spread of this infectious disease. Currently around 4,500 patients are being treated in hospitals and clinics in Basle, Bern, Geneva, Lausanne, Lugano, St. Gallen and Zurich; so far a total of around 10,000 patients have been included in the study. Sociological, case history and clinical data is ascertained in two regular consultations a year. This data and the results of laboratory tests are first rendered anonymous, then sent to a central computer center in Lausanne, where they are stored in a central SQL database.

Amalgamating all the data on one particular patient with a view to facilitating holistic therapy has proved to be very difficult up to now. The information in the SQL database was used primarily for research purposes, and only to a limited extent in the day-to-day care of patients. With the aim of achieving the rapid distribution of and providing rapid and easy access to all the existing medical information, a university institute in St. Gallen began the SHCS Web project in September 1997. Its primary objectives include the development and implementation of tools that allow the hospitals and clinics involved to exchange data via the Web – initially the laboratory results and later the sociological, case history and clinical data as well. The basis for this is a patient database model that integrates all the required information from different data sources.

XML as an integration platform

In 1998, a year after the SCHS Web project was initiated, the team headed by Dr. Grütter and Dr. Fierz designed a solution based on XML and produced a prototype application known as the Electronic Study Form (ESF). The decision to opt for XML was made very early on: "What convinced us about XML more than anything else was its potentially universal availability on the Web, its independence of any proprietary system and its document orientation. By this we also mean its good legibility and its suitability for preserving medical records," explains Dr. Rolf Grütter, head of the research area "Knowledge Media for Professional Communities (KMPC)" of the Institute for Media and Communications Management (chaired by Prof. Dr. Beat F. Schmid) at the University of St. Gallen. "Alternatives to XML such as CORBAMed turned out to be much too complex for our purposes," says Dr. Walter Fierz, Head of the Immunology Division at the Institute for Clinical Microbiology and Immunology.

ESF, an application developed at the institute on the basis of Dynamic HTML, Microsoft’s Data Binding and JavaScript, already uses XML as an interchange format between heterogeneous systems. Since summer 1999, laboratory data from the various sources has been stored in XML format in Tamino, Software AG’s information server – an ideal solution, according to Dr. Walter Fierz: "All the data referring to a particular patient is now integrated - the laboratory data from the central database and eventually also the clinical data which in the past has only been recorded and exchanged on paper. The Tamino solution is extremely convincing." In an initial phase of the project the data is entered and stored in XML format in a local database, which is subsequently made available to all those involved in SHCS. "We hoped that the XML application would accelerate our processes for capturing, transmitting and storing data and reduce the number of errors made in data entry, and it is our impression that these results have been achieved, at least in part. We are evaluating this on a continuous basis by comparing the old processes with the new ones," says Dr. Rolf Grütter. "In the next phase, XML will enable applications such as specialized systems for diagnosis and treatment to be linked up. In addition, we are also considering using the XML database as a storage medium in other centers involved in the long-term study."

Both scientists explicitly emphasize that XML is ideal for representing the kind of structured data usually found in medical documentation. "We map the information in its original structure in XML format, so that it resembles a conventional patient file with a cover sheet and entries following every doctor's visit," comments Walter Fierz. "XML allows stored information to be optimized in line with the way human beings actually think."

The project coordinators give a very positive assessment of their experience so far using an XML database. They are currently looking into developing it further, namely by optimizing the querying of existing data and by providing a direct connection to relational databases. Up to now these have been converted into XML format in a batch process and only then imported.