Comparison of the American-European Consensus Group Sjögren's syndrome classification criteria to newly proposed American College of Rheumatology criteria in a large, carefully characterised sicca cohort

Objective To compare the performance of the American–European Consensus Group (AECG) and the newly proposed American College of Rheumatology ( ACR) classification criteria for Sjogren9s Syndrome (SS) in a well-characterised sicca cohort, given ongoing efforts to resolve discrepancies and weaknesses in the systems. Methods In a multidisciplinary clinic for the evaluation of sicca, we assessed features of salivary and lacrimal glanddysfunction and autoimmunity as defined by tests of both AECG and ACRcriteria in 646 participants. Global gene expression profileswere compared in a subset of 180 participants. Results Application of the AECG and ACRcriteria resulted in classification of 279 and 268 participants with SS, respectively. Both criteria were met by 244 participants (81%). In 26 of the 35 AECG+/ ACRparticipants, the minor salivary gland biopsy focal score was ≥1 (74%), while nine had positive anti-Ro/La (26%). There were 24 AECG−/ ACR+ who met ACRcriteria mainly due to differences in the scoring of corneal staining. All patients with SS, regardless of classification, had similar gene expression profiles, which were distinct from the healthy controls. Conclusions The two sets of classification criteria yield concordant results in the majority of cases and gene expression profilingsuggests that patients meeting either set of criteria are more similar to other SS participants than to healthy controls. Thus, there is no clear evidence for increased value of the new ACRcriteria over the old AECG criteria from the clinical or biological perspective. It is our contention, supported by this report, that improvements in diagnostic acumen will require a more fundamental understanding of the pathogenic mechanisms than is at present available.