The diagnostic value and clinical relevance of salivary gland ultrasound in patients with highly suspected Sjögren’s Disease: a prospective monocentric study

OBJECTIVES: To evaluate the diagnostic accuracy of salivary gland ultrasound (SGUS) in patients with high suspicion of Sjögren's Disease (SjD) and to determine its potential role in the diagnostic process. METHODS: This study is a cross-sectional diagnostic trial based on a prospective cohort, including 171 patients with high suspicion of SjD. SGUS of the parotid glands (PG) and submandibular glands (SMG) was performed according to the OMERACT scoring system. The predictive value of SGUS for diagnostic outcomes and labial salivary gland biopsy (LSGB) results was analyzed. The correlation between SGUS grading and unstimulated salivary flow rates (USFR) was also assessed using statistical tests. RESULTS: Of the 171 participants, 130 were diagnosed with SjD. The OMERACT total score demonstrated moderate efficacy in diagnosing SjD, with an area under the curve (AUC) of 0.78, a sensitivity of 0.52, and a specificity of 0.93. In comparison, LSGB showed the highest diagnostic efficacy (AUC = 0.90), followed by anti-Ro/SSA antibodies (AUC = 0.79). Combining the OMERACT total score with either anti-SSA antibodies or LSGB significantly improved diagnostic performance, achieving a specificity of 1.00. The diagnostic accuracy of parotid gland (PG) and submandibular gland (SMG) ultrasound grading was comparable. However, SMG grading exhibited higher sensitivity but lower specificity than PG grading. Additionally, SGUS grade 3 strongly predicted positive biopsy results (AUC = 0.77) and showed a significant correlation with USFR, with Spearman correlation coefficients of -0.45 for PG and -0.51 for SMG. CONCLUSION: Although the discriminatory efficacy of SGUS in patients highly suspected of SjD is suboptimal, SGUS may offer significant benefits for a specific subgroup of these patients. Grade 3 ultrasound findings are strongly associated with positive biopsy results and USFR, indicating a potential role in diagnosis and disease evaluation. SGUS may be considered for inclusion in future SjD classification criteria.