Semantic Web-Based Information Systems: State-of-the-Art ...

Distributed Patient Identification Protocol 251
clear-text blocking variables comprise the month and year of birth, the patient’s
sex, and place of residence. They evaluated 27,262 record linkage processes performed
in the year 1998 for a database of 101,880 patients. In this case, the record
linkage provided a false positive rate (i.e., patients that were incorrectly selected
as a match) of 0.36% and a false negative rate (i.e., matches in the database that
were not found) of 1.81%. Krieg et al. (2001) emphasise that these figures depend
significantly on the size of the database. Nevertheless, the figures indicate that the
patient identification protocol provides good results even with a rather limited set
of demographics available. It should be noted that in countries that have a national
patient identifier available, the record linkage process would be able to provide
0% false positive and false negative rate in repositories that support the national
patient ID while still providing results in the order of magnitude shown above for
other repositories (i.e., other countries). Additional work will be needed to improve
the internationalisation of the splitting and standardisation algorithms for control
number generation, which currently are based mainly on German experiences with
epidemiological cancer registries. Fine-tuning may be needed for the parameters
of the record linkage process in order to maximise specificity and sensitivity of the
record linkage process.
Conclusion
The patient identification protocol described in this article provides a solution for a
common problem in the health care sector that is likely to become very important
with the increasing mobility of the workforce in Europe — locating and accessing
prior clinical records for the continuity of care. The solution combines techniques
from different domains — control numbers, blocking variables, and record linkage
procedures as used in epidemiological registries, knowledge distribution, and TTP
services from cryptographic communication protocols, semantic annotation, and
ontology-based mediation, core technologies of the Semantic Web. The protocol
reflects the way clinical records typically are stored, indexed, and accessed in today’s
health care information systems. While the advent of a universally accepted standard
for electronic health care records possibly could render the patient identification
protocol obsolete in the future, there is no indication at the moment that such a standard
is going to be established in the foreseeable future, and even then, the issue of
historical records would remain for a number of years. Therefore, the authors believe
that the patient identification protocol can be a significant help in improving access
to clinical information while safeguarding data protection rules and protecting the
patient’s right of self-determination regarding his or her clinical records.
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