ABS0837 MAJOR SALIVARY GLAND ULTRASOUND PERFORMS BETTER THAN UNSTIMULATED WHOLE SALIVA FLOW IN CLASSIFYING YOUNG PATIENTS WITH SJÖGREN'S DISEASE

Background: Sjögren's disease is a systemic autoimmune disorder that affects, among other organs, the major salivary glands. In recent years, salivary gland ultrasound (SGUS) has emerged as a promising tool. In fact, OMERACT has developed a semi-quantitative score that ranges from 0 to 3 and seems useful for diagnosing the disease. The ACR/EULAR 2016 classification criteria for Sjögren's disease place significant weight on unstimulated whole salivary flow (UWSF); however, in younger patients with minimal structural damage, this test may still be normal. Objectives: The aim of this study is to compare the diagnostic performance of SGUS and UWSF in patients under and over 40 years old with suspected Sjögren's disease. Methods: Consecutive patients with suspected Sjögren's disease were included, all of whom underwent SGUS according to the OMERACT score, blinded to clinical data, and a dryness test. All patients underwent UWSF, stimulated (SWSF) with pilocarpine, if UWSF was pathological, and the Schirmer test. UWSF < 0.1 mL/min, Schirmer test < 5mm, and SGUS ≥2 were considered pathological. Results were compared using the ACR/EULAR 2016 classification criteria as the gold standard. Chi-square tests were used for frequency comparisons. Results: A total of 103 patients were included, of which 51 (49.5%) met the ACR/EULAR 2016 criteria. UWSF showed a sensitivity of 52.9% and a specificity of 75%, while SWSF, performed in 27 patients, had a sensitivity of 17.6% and a specificity of 94.2%. The Schirmer test had a sensitivity of 47.1% and a specificity of 80.8%. On the other hand, SGUS demonstrated a sensitivity of 66.7% and a specificity of 76.9%, with positive predictive values (PPV) and negative predictive values (NPV) of 73.9% and 70.2%, respectively. Of the 103 patients, 15 (14.6%) were under 40 years of age, of whom 9 (60%) were classified as having Sjögren's disease. Among the 88 patients over 40, 42 (47.7%) met the classification criteria. Table 1 shows the diagnostic accuracy data for both techniques by age group. Sensitivity of UWSF was significantly higher in patients over 40 compared to those under 40 (p<0.05). In contrast, when comparing both techniques (SGUS vs UWSF), SGUS demonstrated significantly higher sensitivity in the group under 40 (p<0.05). The remaining differences were not statistically significant. Conclusion: SGUS shows greater sensitivity than UWSF for classifying Sjögren's disease, particularly in patients under 40 years old. This can be explained by the preservation of salivary functional reserve in younger patients, which makes detecting functional changes with UWSF more challenging. In contrast, SGUS identifies structural changes in the salivary glands, making it a more precise diagnostic tool in this age subgroup. These findings support its complementary use in clinical practice to improve early and accurate classification of the disease. REFERENCES: NIL . Table 1Comparison of salivary gland ultrasound and unstimulated sialometry by age group in patients with Sjögren's disease.SensitivitySpecificityPPVNPVSGUS<40 years old66,7% 1 66,7%75,0%57,1%≥40 years old66,7%78,3%73,7%72%UWSF<40 years old20,0%80%66,7%33,2%≥40 years old57,1% 2 80,4%72,7%67,3%SGUS: Salivary gland ultrasound, UWSF: Unstimulated whole salivary flow, PPV: Positive predictive value, NPV: Negative predictive value1 Sensitivity of SGUS in < 40 years old vs sensitivity of UWSF in < 40 years old p<0.052 Sensitivity of UWSF in < 40 years old vs sensitivity of UWSF in ≥ 40 years old p<0.05 Acknowledgements: NIL . Disclosure of Interests: None declared . © The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.