THE ROLE OF ULTRASOUND IN THE DIAGNOSIS OF PRIMARY SJOGREN SYNDROME AND ITS CONCORDANCE WITH SALIVARY GLAND BIOPSY

Background Minor salivary gland biopsy (MSGB) is the gold-standard technique for primary Sjogren Syndrome (SSp) but nowadays the use of mayor salivary gland ultrasonography (MSGUS) is increasing because it is a fast and non-invasive technique and with no adverse events for the patient. Objectives To assess the utility of MSGUS as a diagnostic tool for SSp and to study the concordance with MSGB. Methods 72 patients were recruited consecutively with clinical and/or analytical suspicion of SSp, from the Rheumatology outpatient consultations at the Principe de Asturias Hospital (2015-2018). Demographics, clinical and serological data and validated activity indexes, ESSPRI and ESSDAI, were recorded. All patients underwent a MSGB and blindly, both for clinical and histological results, a MSGUS. The histological results were classified according to Chisholm and Mason scores (pathological grades 3/4), and the US results according to the system by Cornec et al. (pathological grade ≥2). The final SSp diagnosis was made using both the 2002 and the 2016 ACR/EULAR classification criteria. The data was analyzed using the software STATA. The validity of the US and the MSGB to diagnose SSp according to the 2002 and 2016 ACR/EULAR classification criteria was evaluated by calculating the percentage of agreement between the tests, along with the specificity (Sp), sensitivity (S), positive and negative predictive values (PPV and NPV) and area under the curve (AUC). Results Descriptive analysis of the main variables is shown in Table 1. Using the MSGB as a gold-standard, the total% of agreement was 78% with a good AUC (0.75) (IC95%0.65-0.84). Using the 2002 classification criteria as a gold-standard, the total% of agreement was 82% for US and 79% for MSGB with an AUC of 0.78 (IC95%0.67-0.88) and 0.80 (IC95%0.70-0.89) respectively. In this case, US had a S of 93% (IC95%0.82-0.99) and a Sp of 62% (IC95%0.41-0.80) whereas MSGB had a S of 78% (IC95%0.64-0.89) and a Sp of 81% (IC95%0.61-0.93). Similar results were obtained using ACR/EULAR criteria: US% of agreement 83%, AUC 0.78 (IC95%0.67-0.90), S 90% (IC95%0.79-0.97) and Sp 67% (IC95%0.43-0.85); while MSGB% agreement 81%, AUC 0.83 (IC95%0.75-0.92), S 76% (IC95%0.63-0.87) and Sp 90% (IC95%0.70-0.99). In addition, 9 patients who fullfilled the 2002 classification criteria with a negative histological result had a pathological US. Conclusion MSGUS has a similar diagnostic value compared to MSGB in patients with SSp, which could be part of the classification criteria used to date. In this series of patients and compared to MSGB, it has a higher sensitivity and a lower specificity, so it could be used as an initial diagnostic method in patients with high suspicion of disease, leaving the MSGB for those cases in which US and other clinical and serological data are inconclusive. With this approach, the disadvantages derived from an invasive technique such as MSGB would be avoided. References [1] Zhou M. Diagnostic accuracy of salivary gland ultrasonography with different scoring systems in Sjogren’s syndrome: a systematic review and meta-analysis. Sci Rep. 2018 Nov 20;8(1):17128. [2] Ultrasonography of major salivary glands compared with parotid and labial gland biopsy and classification criteria in patients with clinically suspected primary Sjogren’s syndrome Esther MosselMossel E, et al. Ann Rheum Dis 2017. Disclosure of Interests None declared