AB0865 THE ROLE OF PLATELETCRIT IN SJÖGREN’S SYNDROME-ASSOCIATED INTERSTITIAL LUNG DISEASE: IS IT A POTENTIAL BIOMARKER?
Authors: E. Cimen Gunes, E. Tekgoz, S. Colak, Ö. Kiliç, M. Çinar, S. Yilmaz
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Platelets have been demonstrated to contribute to the pathogenesis of autoimmune diseases, including rheumatoid arthritis and systemic lupus erythematosus. Plateletcrit (PCT), an essential platelet-related parameter, has been identified as being linked to inflammatory status and disease progression in conditions such as acute hepatitis, non-alcoholic fatty liver disease, and cardiovascular disease. Additionally, there are reports suggesting that platelet count, activation, and PCT may be correlated with the progression of vasculitis, including conditions like Behcet's disease and cutaneous small vessel vasculitis. However, the correlation between PCT and disease activity in both patients with interstitial lung disease (ILD) and those without ILD in Sjögren's syndrome (SS) remains unknown. <h3>Objectives:</h3> To explore the potential of PCT as a novel biomarker for detecting ILD associated with SS (SS-ILD) <h3>Methods:</h3> In this cross-sectional study, patients diagnosed with SS without ILD and those with SS concurrent with ILD, identified based on high-resolution computed tomography (HRCT) findings, were included in the study. The European Sjögren's Syndrome Disease Activity Index (ESSDAI) was employed to assess the disease activity. PCT, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR), C-reactive protein (CRP), and the ESSDAI at the time of diagnosis and after 6 months were compared between SS patients with and without ILD. <h3>Results:</h3> There were a total of 120 patients diagnosed with SS, and among them, 60 (50%) had concomitant with ILD. The mean age of patients with SS-ILD (44 female/16 male) was 65.72 (10.61) years. Non-specific interstitial pneumonia was the most prevalent HRCT finding, observed in 39 (65.0%) patients. At the time of diagnosis and the 6-month follow-up, 45.0% and 26.6% of the patients had diffuse disease on HRCT, and 38.3% and 5.0% had forced vital capacity (FVC) values below 70%, respectively. There was no significant difference in PCT between the two groups, both at the time of diagnosis and at the 6-month follow-up (p=0.856, p=0.569). Among other parameters, the mean values of CRP (p=0.026), MLR (p=0.005), and ESSDAI (p&lt;0.001) were higher in patients with SS-ILD at diagnosis. Additionally, at 6 months, MLR (p=0.012) and ESSDAI (p&lt;0.001) were also higher in SS-ILD patients. The area under the curve (AUC) for PCT was 0.510 at the time of diagnosis and 0.545 at the 6-month follow-up. The sensitivity and specificity for PCT were 86.7% and 33.3% at the time of diagnosis, and 68.3% and 46.7% at the 6-month follow-up, respectively. There was no correlation observed between PCT and ESSDAI at the time of diagnosis and at the 6-month follow-up (p=0.956, p=0.314). Similarly, there was no correlation between PCT and forced vital capacity was observed (p=0.233, p=0.351). However, a strong correlation was observed between FVC at diagnosis and the ESSDAI (r=-0.746, p&lt;0.001). In the multivariate logistic regression analysis (MLRA), there was no observed correlation between PCT and the risk of SS-ILD both at the time of diagnosis and at the 6-month follow-up (p=0.244, p=0.959). Also, in the MLRA, the ESSDAI remained associated with an increased risk of SS-ILD at the 6-month follow-up (OR=1.644, OR=0.244, respectively). <h3>Conclusion:</h3> In this study, unlike other inflammatory markers, PCT showed no discernible association with SS-ILD patients. On the other hand, it appears that the ESSDAI, a metric employed for years, continues to serve as a guiding index in patients with SS-ILD. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>