Background New classification criteria for primary Sjögren’s syndrome (pSS), based on the data from the SICCA registry, have been proposed in 2012 and approved by the American College of Rheumatology (ACR). They differ substantially from the currently used American-European Consensus Group (AECG) criteria in that 1) they do not include subjective ocular and buccal symptoms nor functionnal or morphological tests for salivary glands, 2) they use a new Ocular Staining Score (OSS) as the sole evaluation for ocular involvement, and 3) they consider the association of antinuclear antibody (ANA) titer ≥1:320 and rheumatoid factor (RF) positivity as equivalent to anti-SSA/SSB positivity.
Objectives to evaluate the agreement between the two sets of criteria, and to determinate the factors leading to an eventual discrepancy
Methods This study was conducted in the Brittany monocentric cohort of patients with suspected pSS, included between November 2006 and October 2012. Clinical examination, basic biology, immunological tests and minor labial salivary gland biopsy (SGB) were performed systematically. All patients were evaluated by an ophtalmologist who used fluorescein and Lissamine green to evaluate the presence of keratoconjunctivitis sicca, allowing the subsequent calculation of the OSS. All cases were reviewed by a panel of 3 experts, who determined a clinical diagnosis of pSS or other cause of sicca symptoms. The agreement between the different criteria or tests was studied using Cohen’s κ coefficient.
Results 92 patients have been included in the study (mean age 57±14 years, symptoms duration 6.6±6.2 years, 94.6% females). 43 (46.7%) patients had a clinical diagnosis of pSS, 38 (41.3%) fulfilled AECG criteria and 34 (40.0%) ACR criteria. 27 patients fulfilled both classification criteria, 11 patients only AECG, 7 patients only ACR, and 47 none of them. The agreement between the two criteria was moderate (κ = 0.59). The agreement with clinical diagnosis was higher for AECG (κ = 0.87) than for ACR (κ = 0.64). Xerophtalmia and xerostomia were noted respectively in 92.4% and 93.5% of the patients, suggesting no discriminating capacity between pSS and non-pSS patients. Only 3 patients had ANA≥1:320 and RF but no anti-SSA, but all of them fulfilled both AECG and ACR criteria. The agreement between OSS ≥3 and Schirmer’s test ≤5mm/5min was very low (κ = 0.17). The agreement between these two tests and SGB was similarly low (κ = 0.150 for OSS and 0.324 for Schirmer); they also displayed poor agreement with SSA/SSB positivity (κ = 0.238 for both).
Conclusions ACR 2012 and AECG criteria have a moderate agreement, suggesting that cohorts of pSS patients selected using different classification criteria would not be comparable. The main part of this discrepancy is caused by the differences between OSS and Shirmer’s test. More precise evaluation of the diagnostic value of these ocular tests has to be performed.
Disclosure of Interest None Declared