EDITORIAL - Overlap syndromes: exploring the genetic underpinnings

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Journal of Rheumatology

Editorial

Sep 2009

Overlap Syndromes: Exploring the Genetic Underpinnings

In this issue of The Journal, Mohammed, et al1 describe a group of

patients with erosive arthritis who have features of Sjogren’s

syndrome (SS) sufficient to meet American-European consensus

criteria2. The same patients also meet 1987 American College of

Rheumatology (ACR) criteria for rheumatoid arthritis (RA)3. The

initial reaction to this description might be to dismiss the

importance of the relationship because the patients with arthritis can

be labelled as RA with Secondary SS. But what role do classification

criteria play?

Because of the lack of a single gold standard in most rheumatic

diseases, including SS, development of criteria for diagnosis or

classification has been of continuing interest to rheumatologists. The

main purpose of classification criteria is to standardize clinical

definitions for use in research studies4. Standardized definitions are

needed to allow comparison of studies from different centers. Included

in classification criteria will be findings that distinguish a given

disease from another similar illness. But this requires selection of

criteria with higher specificity, and lower sensitivity. For this

reason, classification criteria differ from diagnostic criteria.

Classification criteria are established to clearly define groups.

Diagnostic criteria are meant for application in an individual

patient. The individual may have a given disease, even if he does not

meet the classification criteria for the disease.

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Read the full editorial here:

http://jrheum.org/content/36/9/1856.full

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