Electronic Health Systems: Integration of Inconsistent Information in
Heterogeneous Multidatabase Health Systems
Carole Alcock, Lois Burgess, Khin Than Win
Faculty of Informatics
Univerisity of Wollongong
Australia
Joan Cooper
Flinders University
Australia
Abstract
The ability to provide accurate, timely information to authorised health providers will unquestionably
improve health care delivery. Essential to this is the development of Electronic Health Record Systems.
Such systems will be dependent on accurate linking of data from disparate healthcare databases. Correct
identification of Electronic Health Records(EHRs) through Universal Patient Identifiers(UPIs) and
guaranteed integrity of content are two elements of importance. Where multiple databases at different
locations are involved, integrity of content is difficult to achieve. This paper explores some of the
problems relating to the integration of often, inconsistent information in heterogeneous multidatabase
health systems. It illustrates this problem with an example of one project undertaken in a regional
healthcare environment. Disparate database systems will continue to exist unless investment is made in
establishing standards both in the structure and organization of databases and in the terminology used
within records. The concept of a semantic network, which allows some flexibility of language in context,
should also be adopted. It is unlikely that all problems of legacy systems will be resolved. However, if
steps are not taken to improve confidence in the Electronic Health Record, the opportunity to greatly
improve health delivery will be lost.
1. Introduction
The ability to provide accurate, timely information to authorised health providers will unquestionably
improve health care delivery. Essential to this is the development of Electronic Health Record Systems.
Such systems will be dependent on accurate linking of data from disparate healthcare databases. Correct
identification of Electronic Health Records(EHRs) through Universal Patient Identifiers(UPIs) and
guaranteed integrity of content are two elements of importance. Where multiple databases at different
locations are involved, integrity of content is difficult to achieve. This paper explores some of the
problems relating to the integration of often, inconsistent information in heterogeneous multidatabase
health systems. It illustrates this problem with an example of one project undertaken in a regional
healthcare environment.
Advances in medical science and management have created an entirely new system of health care, based
on the managed care model. Within this model, care is provided by a collective process, which includes
nursing professionals, consulting physicians, clinicians, lab technicians, diagnostic technologists and
administrative staff. Rarely, today, is a patient treated by one organisation in isolation. Health care is
‘wholistic’ in approach encompassing many health care organisations both public and private. There are
many vital activities in this new health care environment, encompassing areas such as the delivery of
institutional care, health administration, information management and community care activities. All
depend on correct identification of patients (Appavu, 1994).
It has become imperative to uniquely identify patients across multiple providers and to be able to access
patient information from multiple locations in order to support continuity of care. Electronic Health
Records (EHRs) and associated Unique Patient Identifiers (UPIs) are already a feature of the health
system in both public and private health sectors and their use is increasing. The stated objective of the
introduction and use of EHRs and UPIs is better health outcomes.
In an Australian report published in 2000, the following benefits were highlighted:
Improve health outcomes by increasing opportunities for co-ordinated and continuous care within the
health care system;
Provide health providers with access to a more comprehensive patient history, and therefore improve
clinical decision making;
Allow consumers to access their own records;
Be used as a tool for sharing information between health providers and consumers;
Reduce the reliance on the patients own memory to provide medical history;
Reduce possible errors in information transfer, and therefore preventable adverse events;
Reduce duplication of diagnostic testing and imaging, and hence reduce costs;
Improve accountability for health care decision making by making available a better quality of data;
Make more data accessible for research purposes;
Bring together fragmented and dispersed information about an individual to a single accessible point;
Track the use of critical implantable medical devices;
Improve communication between practitioners and people with disabilities by providing a continuous
medical record, particularly where the person has difficulty communicating or where the person has
little family support. (Panacea or Placebo: Linked Electronic Health Records and Improvement in
Health Outcomes, Report to the NSW Minister for Health, December, 2000).
While potential benefits are clear, many problems must be addressed before these can be achieved.
2. Problems with existing medical records
Currently, health records in Australia consist of a mix of electronic and paper-based systems – often
maintained in discrete locations eg. Stand alone computer or health practitioners file. In some cases
patients may take records with them especially when moving interstate, but most often, they remain
property of health provider. Even within the one State there may be difficulties in easily sharing records.
The four NSW Area Health Services have developed a UPI systems but have set up different systems.
However, they are llooking at linking individual records across health providers within their area. An
example is Central Sydney Health Service’s Clinical Information System (CIS) which provides clinicians
with a comprehensive view of patients’ visit history and some medical test/ procedure results. In the
future, this will be extended to a full electronic record, replacing all paper-based medical histories.
Area Health Systems are to be supported by a statewide linkage mechanism by the end of 2002.
A Privacy and Health Background Paper from the NSW Ministerial Advisory Committee (Aug 2000)
listed the following issues for concern:
Current Health Systems –
•the number of legacy health system
•incompatibility problems – problems with transfer of data and providing a complete/accurate medical
history
•inconsistency of standards for coding and classifying patient/clinical info
Limitations of Existing Systems
•Problems outlined above limit the possibility of developing a viable system based on EHR
•No single existing record that contains a complete patient history
•No computerised links to network GPs, hospitals, community health and specialist service
providers
•Problem with transfer of discharge info from hosp to GP/Community health providers
•Problem with linking of systems within hospitals let alone outside health environ (eg. Between
A&E and Intensive care to a ward within the hospital
•No single identifier to enable health providers to identify with certainty a patient
3.Proposals for reform
•Both NSW State and Commonwealth Governments are to work together on EHR development and
implementation
•Improve links among all health professionals within and across hospitals and with other health
professionals
•Establish UPI for every individual in NSW irrespective of at what point they have entered the health
system
Proposed Features of EHR
•Accessible to individual consumer and provider independent of location incorporating privacy
and security safeguards
•Individual consent for inclusion/transfer in info amongst providers
•Records to contain clinical records, advice, specialist referrals, pharmacy details, diagnostic tests
and results
•Provide all health providers with info about patient med history with patient consent
•Assist in clinical decision making
•Enable collection of data for use in medical research, measure quality and performance of health
care provision, give consumer better health choices.
However, underlying the effective development of an HER is the problem of heterogenous /disparate
databases including legacy systems.
4. Database inconsistencies
Getta (2001) Integration of inconsistent information in heterogeneous multidatabase systems:
The trend towards globalisation of information systems requires seamless integration of many independent
sources of information (Sheth & Larson, 1990; Tsai & Chen, 1993; Tseng & Wang, 1993a). A concept of
multidatabase systems has been introduced some time ago to provide the architectural backgrounds for the
systems that integrate a large number of local and independent database systems into a single global
database system. Strong autonomy of the local database systems and the delays caused by the wide-area
networks make preservation of data consistency in multidatabase systems too time consuming. This is
why the global consistency is frequently sacrificed in order to preserve the autonomy of local systems and
to speed up processing of distributed transactions. It is inevitable that at some point in time integration of
the local databases may provide inconsistent results. Multidatabase systems belong to a category of global
information services where data inconsistencies are a common problem.
A typical environment where we have to deal with different representations of the same data objects
and/or association is a group of autonomous medical database systems recording information related to
patients and their health records. Frequent migration of patients from area to area causes multiple
registrations of the same patients in different database systems. A high level of autonomy of the local
systems and lack of global control contributes to construction of similar and not identical descriptions of
the same patients in different databases. Other researchers who make similar claims to the above are
(Garcia-Solaco, Saltor and Castellanos, 1995; Agarwal, Keller, Wiederhold & Saraswat, 1995; Reddy &
Gupta, 1994; Lim, Srivastava & Shekhar, 1994).
5. Data linking
Problems arise in any attempt to link health records across disparate database systems. This was evident
in a recent project, which focused on maternal and infant health records of the South West Sydney Area
Health Services and the development of software to link disparate legacy health databases within the
Maternal and Infant Network (MINET). MINET is a long term research project studying longitudinal
health data of over 60,000 mothers and babies in the South West Sydney Area Health Service Division
conducted through the Simpson Centre for Health Service Innovation. The Centre has vast amounts of
data from Hospitals, Community and General Practices. Its primary role is in health care research. The
study aims to provide vital information on health services in order to improve decision making as to the
types of health provision required throughout the region and to aid in the development of health policy.
While there is an immediate demand for the integration of the legacy databases, the long term plan has
been to make available at the different health care centres, records of mothers and their children which
will allow for fully informed decision making when it comes to health care provision. Effective linkage of
data from different data sources is essential if appropriate comparison of data is to be achieved.
6. The MINET / LinkIT project
The MINET data involved are from hospitals, clinics and well-baby centres. To capture all health
information of the mother and infant, integration of databases is needed.
Data items are linked
accordingly with the LinkIT software developed by the team at the University of Wollongong. The system
does not conflict with the existing systems and does not disrupt current workflow. It amalgamates well
with the ongoing processes. The software acts as an engine with translation and linking processes. The
translation process conducts the necessary data mining for selecting the data source and the linking
process matches and links the data. Currently, data integration is based on the matching of source data in
text format. As there were security and privacy concerns, the development team used the dummy data
during the development, with ‘real life’ data testing being done at the Simpson Centre with an
appropriately authorised person.
As the patients are not uniquely identified, the data matching and linking are based on the Medical Record
Number (MRN) and a number of attributes which include: Mother’s Community Medical Record
Number (MCMRN), Baby’s Community Medical Record Number (BCMRN), Mother’s Hospital Medical
Record Number (MHMRN), Baby’s Hospital Medical Record Number (BHMRN) and attributes such as
Mother’s date of birth, visit date, admit date, discharge date and baby’s date of birth.
Matching of the data presents a challenge because the one individual may have several identifiers of the
same type in different databases. This is particularly a problem for women whose marital status and name
may vary and also for children within ‘blended’ families. This highlights the fact that unique identifiers
are of utmost importance in the linking of databases. Data integrity is of concern because health care
providers and researchers need to decide whether the records with other possible matches are for the same
individuals’ records or of different individuals. As well, because of errors in data entry or transcription,
there may be more than one person with the same medical record number. Clearly, if the data integrity
cannot be guaranteed, the result will have an impact on treatment, decision making, statistical analysis and
the measurement of health outcomes.
As the linking system involved disparate legacy databases with different data attributes, work on this
project has been a challenge. The LinkIT Software aims to link records in timely manner with precision
and accuracy.
Privacy and security can be maintained as in paper based record systems. Proper
authorisation and authentication of the user for data editing is required and any amendment made will be
logged in the audit trail. However, further work is needed on the system. Experience with this project has
emphasised the problems which arise because of difficulties in establishing a unique identifier for
individuals, especially when this is complicated by changing family situations of participants as is the case
in the South West Sydney region.
7. Approaches elsewhere
Van Wingerde, et al (1996) describes the W3-EMRS architecture which was designed to access clinical
data at the Children’s Hospital, Boston. The demonstration project provided access over the web to a
single EMRS database from which all identifiable data had been removed, but multiple database access
was an objective. The desirability of web access is clear although reservations might be expressed from a
security perspective. The W3 EMRS Project paper on multiplatform Internet access, emphasises the need
for a collaborative approach to the implementation and deployment of an Electronic Medical Record
System (EMRS). Objectives of this project focus on standards. Among the issues raised are the need for
the establishment of ‘a canonical electronic medical record structure with supporting data abstraction
processes to provide consistent views of medical information independent of underlying database
structure’ and the employment of ‘standardised medical vocabularies in the EMRS’ and the provision for
‘translating / mapping of local non-standardised medical vocabularies.’
Discussion on standards has been an important focus of a the research into an ERMS. An important issue
is that of varying vocabulary and medical terminology. Variability of terminology complicates retrieval.
The National Library of Medicine is attempting to address the problem with it’s development of the
Unified Medical Language system (ULMS). A’Metathesaurus’ has been developed to address the
problem of multiple medical vocabularies. This consists of a database of information relating to medical
terminology. A UMLS semantic network is another aspect of this project. This, it was believed would
allow for greater flexibility and be a basis for achieving the objective stated above: relating to the
employment of ‘standardised medical vocabularies in the EMRS’ and the provision for ‘translating /
mapping of local non-standardised medical vocabularies.’
It has been noted that substantial effort is required in “gluing” a new interface to an existing database. The
problem is compounded when multiple databases are involved, some at distant sites. The particular
difficulties for remote users need to be considered. Intensive care was another area where the integration
of heterogeneous data sources was complex but would be advantageous. Knowledge gaps where retrieval
procedures and terminology are concerned may cause problems.
8. Conclusion
Concerns over privacy and integrity of the Electronic Health Record will continue to be raised and need to
be addressed at both the technical and legislative levels. If the benefits of the EHR are to be achieved,
however, much more attention will need to be paid to the problems of data linking. Disparate database
systems will continue to exist unless investment is made in establishing standards both in the structure and
organization of databases and in the terminology used within records. The proposals outlined in the W3 –
EMRS project in the US are positive steps in this direction. The concept of a semantic network, which
allows some flexibility of language in context, should also be adopted. It is unlikely that all problems of
legacy systems as were seen in the LinkIT project outlined above, will be resolved. However, if steps are
not taken to improve public and healthcare confidence in the Electronic Health Record, the opportunity to
greatly improve health delivery will be lost.
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