Ab0955 Evaluation of Choroidal Thickness and Choroidal Vascularity Index in Patients With Axial Spondyloarthritis and Determination of the Relationship With Disease Activity

Background: Axial spondyloarthritis (axSpA) is an inflammatory disease with articular and extra-articular involvement and uveitis is a common extra-articular involvement [1]. There are some studies showing that choroidal thickness (CT) is increased in patients with Ankylosing Spondylytis (AS) [2]. There is only one study in the literature evaluating choroidal vascularity index (CVI) in patients with AS and that study, CVI was evaluated during acute anterior uveitis in AS patients [3]. However, there is no study in the literature evaluating the relationship between CVI and disease activity in patients with axSpA. Objectives: To evaluate the CT and CVI in patients with axSpA and to determine its relationship with disease activity. Methods: According to Assessment in Spondyloarthritis International Society (ASAS) classification criteria for axial spondyloarthritis [4], 32 axSpA patients (axSpA group) and 44 healthy volunteers (control group) were recruited. Number of participants was determined assuming a 63.15 µm mean difference and 2.87 µm standard deviation of choroidal vascularity index with 80% power and 5% significance [3]. Demographic, clinical and laboratory features were recorded. SpA activity was assessed by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Bath Ankylosing Spondylitis Fuctional Index (BASFI) and, global patient assessment (with Visual Analogue Scale-VAS) scores were recorded. Two different ophthalmologists blinded to the groups performed optical coherence tomography (OCT) evaluations and the data of the right eye were recorded. CT was measured at 500 micrometers (µm), 1000 µm, 1500 µm nasal to the fovea, 500µm, 1000µm, 1500µm temporal to the fovea and subfoveal region. CVI was calculated and recorded as luminal area (LA)/total choroidal area (TCA). Results: Age, height, weight and body mass index were similar in two groups (Table 1). Patient global VAS was 4.06±2.55, BASDAI score was 4.11±1.89 and BASFI score was 3.41±1.95 in axSpA group. HLA-B27 was positive in 5 (15.6%) axSpA patients. Mean disease duration was 9.21±8.07 years. TCA, LA and stromal area were significantly increased in axSpA group compared to control group (Table 2). CVI and choroidal thicknesses were similar between groups (Table 2). A positive correlation was found between Nasal 1000 µm CT, Temporal 1000 µm CT and CRP level in axSpA group (r=0.359, p=0.044; 0.442, p=0.011 respectively). No correlation was found between choroidal thicknesses, BASDAI, BASFI and patients global VAS scores. Conclusion: It was found that total choroidal area, luminal area and stromal area increased in patients with axSpA compared to healthy subjects, but this increase was not associated with disease activity and functional level. REFERENCES: [1] Braun J, van den Berg R, Baraliakos X, Boehm H, Burgos-Vargas R, Collantes-Estevez E, et al. 2010 update of the ASAS/EULAR recommendations for the management of ankylosing spondylitis. Ann Rheum Dis 2011;70:896-904. [2] Kola M, Kalkisim A, Karkucak M, Turk A, Capkin E, Can I, et al. Regarding Comments by Yolcu et al. on "Evaluation of Choroidal Thickness in Ankylosing Spondylitis Using Optical Coherence Tomography". Ocul Immunol Inflamm 2015;23:465-6. [3] Balci S, Turan-Vural E. Evaluation of changes in choroidal vascularity during acute anterior uveitis attack in patients with ankylosing spondylitis by using binarization of EDI-optical coherence tomography images. Photodiagnosis Photodyn Ther. 2020 Sep;31:101778. [4] Rudwaleit M, van der Heijde D, Landewe R, et al. The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection. Ann Rheum Dis 2009; 68: 777–783. Acknowledgements: NIL. Disclosure of Interests: None declared.