Diagnostic performance of salivary gland ultrasonography using the OMERACT scoring system in Sjögren disease: A cross-sectional diagnostic accuracy study.

BACKGROUND: Sjögren disease (SjD) is an autoimmune disorder characterized by salivary and lacrimal gland dysfunction. Salivary gland ultrasonography (SGUS) is a non-invasive, accessible imaging modality for assessing glandular structural changes, although its diagnostic performance compared with conventional diagnostic tests requires further evaluation. OBJECTIVES: To evaluate the diagnostic accuracy of OMERACT-scored salivary gland ultrasonography in patients with suspected primary or secondary SjD. DESIGN: This is a cross-sectional diagnostic accuracy study of salivary ultrasonography. METHODS: This study was conducted in the Department of Rheumatology, Bangladesh Medical University, from February 2023 to February 2024. Patients presenting with sicca symptoms were classified according to the 2016 ACR/EULAR classification criteria, which served as the reference standard. All participants underwent clinical evaluation, Schirmer's test, unstimulated whole salivary flow rate (UWSFR), anti-SSA/anti-SSB antibody testing, and SGUS of the parotid and submandibular glands. SGUS images were scored using the OMERACT semiquantitative grayscale scoring system (0-3 per gland) by a blinded examiner. Diagnostic performance was assessed using sensitivity, specificity, and receiver operating characteristic (ROC) curve analysis. RESULTS: Among 100 participants, 50 fulfilled the 2016 ACR/EULAR classification criteria for SjD. Patients with SjD had significantly higher mean SGUS scores and lower mean UWSFR compared with those without SjD (p < 0.001). An OMERACT SGUS grade ≥2 in at least one gland demonstrated 84% sensitivity and 92% specificity. A total SGUS score ≥4 showed 88% sensitivity and 86% specificity, whereas a score ≥6 provided 100% specificity with reduced sensitivity (64%). SGUS showed excellent diagnostic performance with an area under the ROC curve (AUC) of 0.94 (95% CI: 0.90-0.99). Compared with SGUS, Schirmer's test demonstrated lower diagnostic accuracy (sensitivity 65.3%, specificity 52%), while UWSFR showed high sensitivity (92%) but limited specificity (48%). SGUS score showed a weak positive correlation with disease duration (r = 0.33, p < 0.05). CONCLUSION: OMERACT-scored salivary gland ultrasonography demonstrated excellent diagnostic accuracy and superior specificity compared with conventional functional tests. SGUS may serve as a valuable non-invasive adjunctive tool in the diagnostic evaluation of patients with suspected SjD.