eHEALTH INTEGRATOR –
CLINICAL DATA INTEGRATION IN LOWER AUSTRIA
*

Nevena Stolba*, Alexander Schanner
†

*Woman’s Postgraduate College for Internet Technologies, Institute of Software Technology and Interactive Systems,
Vienna University of Technology, Favoritenstr. 9-11/E188, 1040 Vienna, Austria
Fax: +431 588018 18895
stolba@wit.tuwien.ac.at

†
Program Manager ARGE ELGA,
Schiffamtsgasse 15, 1020 Vienna, Austria
alexander.schanner@arge-elga.at




*
This research has been partly funded by the Austrian Federal Ministry for Education, Science and Culture, and the European Social Fund
(ESF) under grant 31.963/46-VII/9/2002.
Keywords: interoperability in healthcare, IHE, XDS, data
warehouse

Abstract
Interoperability between medical information systems is
becoming a necessity in modern health care. Under strong
security measures, healthcare organisations are striking to
unite and share their (partly very high sensitive) data assets in
order to increase the quality of care and to reduce treatment
costs. Due to the immense volumes of medical data, the
architecture of the future healthcare networks focuses more
on interoperability than on integration. Standardized
electronic documentation and communication are crucial
factors for the necessary modernisation of healthcare systems.
In this paper, we present a case study about the “NÖMED
WAN Patientenindex” project, in which an IHE-based
healthcare network for exchange of patient’s documents was
developed. “NÖMED WAN Patientenindex” is currently the
largest eHealth projects in German-speaking region. It is
being implemented in Lower Austria and it involves the
stepwise creation of an electronic health network. The goal of
the project is the integration of 27 hospitals in this area and
building of a shared directory which will contain data about
patients’ treatments, medical summaries, hospital stays and
diagnoses. Due to the consolidation of the mostly
heterogeneous hospital information systems, physicians are
now able to view all the existing examination findings and
reconstruct the medical history of their patients.

1 Introduction
Despite the scientific and technological development progress
over the recent years in the healthcare delivery, a significant
portion of the decision-making information on the treatment
of a patient’s illness is still based on unstructured information
or even hand-written notation. Paper based patient health
record has many advantages: it is well-established, it is easy
to use, understand and browse. Nevertheless, information
aggregation and processing of such data has major
limitations.
The vast majority of patients receive their healthcare from
multiple healthcare providers. Hospitals, physicians, recovery
centres, laboratories, pharmacies and health insurance
institutions have each their own, isolated patient records and
therefore fragmental knowledge about the patient’s health
condition is stored on different sites. Absence of integrated
healthcare bears the risks of medical treatment errors,
duplicate examinations, lack of coordination and increased
therapy costs. Using genomics data for personalisation of
health care and for improving health knowledge is one of the
major research concerns in modern health informatics. The
fulfilment of this issue depends on the interoperability of
biomedical information and patient’s health records.
Although the advantages of healthcare information integration
are clear, divergence still exists about how such integration
should be achieved. Because of the complexity of clinical
information, very heterogeneous and rapidly growing source
databases involved, an integrated system needs to fulfil some
important requirements like flexibility, maintainability and
scalability.
The contribution of this paper is the presentation of a case
study about the integration of 27 hospitals in Lower Austria
into a shared network for exchange of patient’s health care
documents. This seminal, successfully implemented project
endorses the use of the future-proof Integrated Healthcare
Enterprise (IHE) [11] standard, which protects the
investments through its vendor-independent extendibility.
The rest of the paper is organized as follows: we briefly
present the IHE standard, in particular the XDS integration
profile. Then we show a case study about the IHE-based
healthcare network developed in Austria. We mainly focus on

creation of Patient index and Medical History as well as on
Cross-Enterprise clinical document sharing model. In
Security section, we describe the main security aspects for
guaranteeing patient’s privacy. In related work, we present
the most important international standards for healthcare
domain. Subsequently, we shortly describe a federated data
warehouse model - an alternative approach of consolidation
of heterogeneous medical information systems and we
finalise the paper with the conclusion.

2 Integrating the Healthcare Enterprise (IHE)
Integrating the Healthcare Enterprise (IHE) [11] is an
initiative designed to stimulate the integration of the
information systems that support modern healthcare
institutions. IHE initiative recommends the use of existing
standards, such as HL7 [8], DICOM [5], IETF and others,
instead of defining new integration standards.
IHE is strongly supported by the industry: more than 160
companies have developed IHE-compliant systems between
1999 and 2005 and participated in cross-vendor testing
events, Connect-a-thon [9, 10], organized by IHE. This means
that standards recommended by IHE have a high probability
of a quick uptake in the medical market [13].
IHE is organized by clinical and operational domains. For
each domain, integration and information sharing preferences
are defined. The aim of each IHE domain is to promote the
implementation of standard-based interoperability solutions in
its specific area, to improve information sharing,
workflow and patient care. Following active IHE domains are
available: Cardiology, Eye Care, IT Infrastructure,
Laboratory, Patient Care Coordination, Patient Care Devices
and Radiology.
IHE IT Infrastructure Technical Framework (ITI TF) is an
ongoing expanded document, which defines specific
implementations of established standards in order to support
optimal patient care through beneficial sharing of medical
information. This document illustrates IHE functionality
showing the transactions organized into functional unites
called integration profiles.
IT Infrastructure domain consists of following integration
profiles:
• Retrieve Information and Display (RID)
• Enterprise User Authentication (EUA)
• Patient Identifier Cross-referencing (PIX)
• Patient Synchronized Applications (PSA)
• Consistent Time (CT)
• Patient Demographics Query (PDQ)
• Audit Train and Note Authentication (ATNA)
• Personal White Pages (PWP)
• Cross-Enterprise Document Sharing (XDS)
Last integration profile mentioned (XDS) specifies how to
manage and share electronic clinical documents that
participating healthcare providers are willing to share. Since
this corresponds to our research issue, we will describe it in
more detail in the next section.
2.1 Cross-Enterprise Document Sharing (XDS)
The task of the Cross-Enterprise Document Sharing (XDS)
integration profile is to facilitate registration, storing and
sharing of healthcare documents across healthcare enterprises.
Thereby, XDS is not concerned with the content of the
documents – it handles standard or formatted text as well as
images or structured clinical information.
XDS acts on the assumption that healthcare enterprises
participating in the document exchange network build a group
called Clinical Affinity Domain. A Clinical Affinity Domain
is a group of healthcare enterprises that have agreed to work
together using a common set of policies and share a common
infrastructure [3]. The polices include specification of patient
identifiers, definition of document format, structure and
content, agreement on access control as well as assignment of
metadata representation of the clinical documentation. These
are necessary prerequisites for ensuring interoperability
between heterogeneous healthcare information systems.
Actors involved with XDS and the transactions between them
are depicted in Figure 1.

Patient Identity Source
Document Registry Document Consumer
Document RepositoryDocument Source
Patient Identity
Feed
Query
Registry
Register
Document Set
Provide &Register
Document Set
Retrieve Document

Figure 1: Cross-Enterprise Document Sharing Diagram
(XDS) [3]

Document Source is the healthcare institution participating
the document sharing network. Document source provides the
documents to be shared and corresponding metadata, which is
used for document registration.
Document Registry contains and administers the metadata of
the documents, and can be queried in order to detect the
designated Document Repository.
Document Repository stores documents to be shared. Since
these are very high-sensitive data, Document Repository can
not be queried. Users (Document Consumers) need to know
document’s unique ID (stored as metadata in Document
Registry) in order to retrieve the desired document.
Patient Identity Source is responsible for assigning patient
identifiers.
3 Case Study: NÖMED WAN Patientenindex
3.1 Healthcare Providers Landscape in Lower Austria
The Lower Austrian Health and Welfare Fund Area of Health
(NÖGUS) is in charge with financing, quality assurance and
supply planning for the 22 hospitals distributed over 27
locations and embracing approx. 8200 beds. Currently, 7
different HIS from 4 different vendors are in use.
Additionally to the hospitals, around 3000 general