Automatic Record Hash Coding and Linkage for Epidemiological Follow-up Data Confidentiality

C. Quantin; H. Bouzelat; F. A. Allaert; A. M. Benhamiche; J. Faivre; L. Dusserre

doi:10.1055/s-0038-1634527

Methods of Information in Medicine, Table of Contents

Methods Inf Med 1998; 37(03): 271-277
DOI: 10.1055/s-0038-1634527

Original Article

Schattauer GmbH

Automatic Record Hash Coding and Linkage for Epidemiological Follow-up Data Confidentiality

C. Quantin

¹Department of Medical Informatics, Teaching Hospital of Dijon, France

,

H. Bouzelat

¹Department of Medical Informatics, Teaching Hospital of Dijon, France

,

F. A. Allaert

²W2 “Data Security”, European Federation of Medical Informatics

,

A. M. Benhamiche

³Registry of Digestive Cancers in Burgundy, Burgundy University, Dijon, France

,

J. Faivre

,

L. Dusserre

¹Department of Medical Informatics, Teaching Hospital of Dijon, France

› Author Affiliations

Abstract

A protocol is proposed to allow linkage of anonymous medical information within the framework of epidemiological follow-up studies. The protocol is composed of two steps; the first concerns the irreversible transformation of identification data, using a one-way hash function which is used after spelling processing. To avoid dictionary attacks, two large random files of keys, called pads, are introduced. The second step consists in the linkage of files rendered anonymous. The weight given to each linkage field is estimated by a mixture model, the likelihood of which being maximized with the Expectation and Maximization (EM) algorithm. The performance of this method has been assessed by comparing record linkage, based on exclusive use of the automatic procedure, with a manual linkage, obtained by the Burgundy Registry of Digestive Cancers. The result of the linkage of a file of 2,847 cancers with a file of 388,614 hospitalization stays in the Dijon university hospital showed a sensitivity of 97% and a specificity of 93%.

Keywords

Epidemiological Survey - Record Linkage - Non-reversible Encryption - Hash-coding - Security

Full Text

References

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