Background Ultrasound of major salivary glands (sUS) is an upcoming diagnostic method to assess the involvement of major salivary glands in primary Sjögren's syndrome (pSS). In the AECG, ACR and recently published ACR-EULAR criteria, a positive salivary gland biopsy and/or presence of anti-SSA antibodies are necessary to classify a patient as pSS, while sUS is not included as a diagnostic item.
Objectives To assess whether combining anti-SSA antibody status with sUS outcome can predict classification of patients as pSS in our inception cohort study.
Methods Consecutive outpatients clinically suspected with pSS underwent sUS of the parotid and submandibular glands. Parenchymal echogenicity, homogeneity, hypoechogenic areas, hyperechogenic reflections and clearness of salivary gland border were scored according to the Hocevar scoring system (total score 0–48).1 Positive sUS was defined as total score ≥15. Patients underwent a diagnostic work up according to the AECG, ACR and ACR-EULAR criteria. We analyzed the predictive value of the combination of anti-SSA antibody status and sUS outcome for classification as pSS or non-pSS. Separate analyses were done considering either i) parotid gland biopsy or ii) labial gland biopsy as an item, when applying these classification criteria.
Results Anti-SSA antibody status was positive in 53 (51%) patients and sUS was positive in 40 (39%) patients.
When parotid gland biopsy outcome was considered as an item of the criteria, 45 of 97 patients were classified as pSS according to the AECG, 44 of 97 according to the ACR and 52 of 99 according to the ACR-EULAR criteria. The combination of presence of anti-SSA antibodies with positive sUS showed a very high positive predictive value for classification as pSS (94–97%) and the combination of absence of anti-SSA antibodies with negative sUS highly excludes classification (negative predictive value 98–100%).
When labial gland biopsy outcome was considered as an item of the criteria, 49 of 96 patients were classified as pSS according to the AECG, 43 of 93 according to the ACR and 55 of 97 according to the ACR-EULAR criteria. The combination of presence of anti-SSA antibodies with positive sUS showed a high positive predictive value for classification as pSS (94–97%). However, the combination of absence of anti-SSA antibodies with negative sUS did not per se exclude classification (negative predictive value 89–93%).
Conclusions In our prospective inception cohort study derived from daily clinical practice, the combination of presence of anti-SSA antibodies and positive sUS outcome highly predicts classification as pSS according to the AECG, ACR and ACR-EULAR classification criteria.
Hocevar et al. Rheumatology (Oxford) 2005;44:768–72.
Disclosure of Interest None declared
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