Ab0856 Correlation Between Oxford Grading of Corneal Staining Score and Sicca Test Included in Acr-Eular 2016 Classification Criteria for Primary Sjögren Syndrome

Background: Primary Sjögren's Syndrome (pSS) is an autoimmune disease characterized by dryness of mucous membranes, especially of the eyes and mouth, and by infiltration of the affected tissues by lymphocytes. The Oxford grading scale (OGS) evaluates corneal damage that can be associated with dry eye disease. The measurement of the ocular surface damage is part of the ACR-EULAR 2016 classification criteria, using the Ocular Staining Score (OSS) or van Bijsterveld score (vBs). Although OGS is not considered within these criteria, this test could play a role in identifying patients with severe dryness during the pSS diagnostic process. Objectives: To explore the correlation between the Oxford test and the Schirmer test in patients with primary Sjögren's Syndrome meeting ACR-EULAR 2016 classification criteria without OSS or vBs. The correlation with unstimulated (UWSF) and stimulated whole salivary flow (SWSF) was also examined. Methods: Clinical data from patients included in Sjögren Syndrome and Atopic Dermatitis cohorts' generation and multi-omics characterization project (SSAD project) were analyzed. For each patient, Schirmer test, OGS test, UWSF and SWSF were performed following standard protocols. OGS compares the overall appearance of the patient's corneal staining with a reference figure, simulating the pattern of staining encountered in dry eye disease. OGS divides corneal staining into six groups according to severity, ranging from 0 (absent) to 5 (severe), and its value is expressed as the sum of OGS of both eyes. OGS result is considered pathological if the result is different to zero. Schirmer test was considered pathological if ≤5 mm after 5 minutes, and its value was presented as the mean of both eyes. UWSF and SWSF were collected for 5 minutes and expressed in mL/min. UWSF was considered pathologic if ≤1mL/min. Spearman correlation was used to analyze correlation between OGS and Schirmer test, OGS and UWSF and OGS and SWSF, using absolute values. Consecutively, Schirmer test and UWSF results were converted to dichotomic values, namely pathological vs. non-pathological, and a Chi squared test was performed with p-value obtained by Monte Carlo simulation. Results: Twenty-four pSS patients meeting ACR-EULAR 2016 classification criteria were included in the analysis, with a total of 29 measures. Five patients were evaluated twice with a span of at least 12 weeks between measures. Twenty-three patients were females (96%), with a mean age of 60.5 years. All patients with a pathological OGS associated a pathological Schirmer test. A negative correlation was found between both tests (a higher OGS was correlated with a lower Schirmer test result) with a rho value of -0.59 (p=0.0025) (Figure 1). Results were similar after considering only the baseline measure of each patient. Chi-square test confirmed this correlation when comparing pathological vs. non-pathological results (p= 0.0399). No significant correlation was found between OGS and UWSF or SWSF. Conclusion: Alterations found by OGS correlated with a pathologic Schirmer test in pSS patients. Corneal damage found by OGS does not seem to be related with oral dryness measured by salivary flow. OGS could play a role in identifying patients with severe eye dryness during the pSS diagnostic process. REFERENCES: NIL. Table 1. Correlation between OGS and Schirmer test Acknowledgements: NIL. Disclosure of Interests: None declared.