Ab0738 elevated platelet count is a risk factor for refractory takayasu arteritis

Background Takayasu arteritis (TAK) is a chronic systemic vasculitis that mainly affects the aorta and its major branches. This chronic relapsing disease is relevant to significant morbidity and treatment remains challenging [1]. Early identification of refractory TAK is helpful to improve the long-term prognosis of the disease. In recent years, platelets have been recognized as important markers for various types of diseases [2]. Platelet counts may indicate the activity of autoimmune disease as well as responsiveness to anti-inflammatory therapy and presence of various comorbidities [3]. Multiple studies have demonstrated that platelet count of TAK patients was significantly increased, especially in the active phase, which was significantly higher than that in the inactive phase [4-8]. Objectives Platelets have been recognized as important markers for various types of diseases. The aim of our study was to investigate whether platelet count could be the risk factor of refractory Takayasu arteritis (TAK). Methods In this retrospective study, 57 patients were divided into groups with or without refractory TAK. We compared the clinical manifestations, laboratory parameters, and medication between the two groups. The logistic regression analysis was used to identify the risk factors of refractory TAK. Results Among the 57 patients, 18 cases (31.6%) were considered to have refractory TAK within 1 year of initiation of medication in our hospital. Refractory TAK patients had higher level of platelet (PLT) than non-refractory TAK patients (305.5 vs. 272.0, 10 9 /L, P=0.043). PLT was positively correlated with ESR (r=0.502, p＜0.001), hs-CRP (r=0.529, p＜0.001), IgA (r=0.322, p=0.016), IgG (r=0.419, p=0.001), IgM (r=0.343, p=0.010), C3 (r=0.554, p＜0.001). For PLT, the area under the ROC curve was 0.668 (95% CI 0.515 to 0.822, p=0.043) and the best cut-off value was 296.5×10 9 /L. The level of PLT greater than 296.5×10 9 /L was found to be statistically related to refractory TAK (OR [95%CI] 4.000 [1.233-12.974], p=0.021). Conclusion Clinicians should pay close attention to platelet levels in patients with TAK. For TAK patients with elevated platelet levels, earlier and more aggressive treatment is needed, and antiplatelet therapy is recommended as appropriate. References [1]Abisror, N., et al., Tocilizumab in refractory Takayasu arteritis: A case series and updated literature review. Autoimmunity reviews, 2013. 12(12): p. 1143-1149. [2]Yun, S., et al., Platelet Activation: The Mechanisms and Potential Biomarkers. BioMed Research International, 2016. 2016: p. 1-5. [3]Gasparyan, A.Y., et al., The Platelet-to-Lymphocyte Ratio as an Inflammatory Marker in Rheumatic Diseases. Annals of Laboratory Medicine, 2019. 39(4): p. 345-357. [4]Pan, L., et al., Platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio associated with disease activity in patients with Takayasu’s arteritis: a case-control study. BMJ Open, 2017. 7(4): p. e014451. [5]Peng, Y., J. Guo and Y. Deng, The role of mean platelet volume in patients with Takayasu arteritis. Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 2017. 54(2): p. 273-278. [6]Wang, X., et al., Inflammation Is Associated With Platelet Coagulation Function Rather Than Enzymatic Coagulation Function in Patients With Takayasu Arteritis. Int Heart J, 2017. 58(4): p. 589-592. [7]Chen, R., et al., Serum complement 3 is a potential biomarker for assessing disease activity in Takayasu arteritis. Arthritis Research & Therapy, 2021. 23(1). [8]Seringec Akkececi, N., et al., The C-Reactive Protein/Albumin Ratio and Complete Blood Count Parameters as Indicators of Disease Activity in Patients with Takayasu Arteritis. Medical Science Monitor, 2019. 25: p. 1401-1409. Acknowledgements: NIL. Disclosure of Interests None Declared.