Background Axial spondyloarthritis (axSpA) is a chronic inflammatory disease which includes radiographic subtype [ankylosing spondylitis (AS)], and non-radiographic subtype (nr-axSpA)^[1]. Chronic inflammatory disorders, such as axSpA, are associated with increasing cardiovascular (CV) risk which is mainly due to the inflammatory burden^[2].

Objectives Evaluation of endothelial dysfunction and subclinical atherosclerosis in axSpA and comparison between in AS and nr-axSpA regarding disease activity, functional status and Subclinical atherosclerotic disease.

Methods Eighty Patients fulfilling the ASAS classification criteria plus 60 healthy individuals were included in this study. Patients were divided into two groups; 50 patients with AS (GI) and 30 patients with nr-axSpA (G II), while G III was the control group. Patients with nr-axSpA were defined as the absence of definite sacroiliac (SI) joint changes on plain radiograph but with active sacroiliitis on MRI and at least one of the characteristic traits of SpA according to the 2009 ASAS criteria^[3].

Demographic data, duration of the disease, delay in diagnosis, extra-articular manifestations, smoking, comorbidities and detailed medication history were taken.

Disease activity were assessed by Ankylosing Spondylitis Disease Activity Score (ASDAS) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI).

Physical function was assessed by the Bath Ankylosing Spondylitis Functioning Index (BASFI) & patient-reported outcome measures (PROMs).

Serum endothelin-1 and carotid intima-media thickness (cIMT) were measured to assess endothelial dysfunction and subclinical atherosclerosis.

Results There was no significant difference between the GI & GII regarding age and gender (p>0.05), while AS patients had longer mean disease duration than nr-axSpA (6.6 years vs 3.7 years, P < 0.001). Forty-eight patients out of 50 in G I were receiving biological therapy while 23 patients from 30 in G II were receiving biological therapy with significant difference between the two groups (p=0.02). There were no significant differences between GI and GII regarding comorbidity, and smoking status (p>0.05).

Regarding disease activity; we found no significant difference between GI and GII in ASDAS-CRP (2.0±0.9, & 2.2±1.02 respectively), also there was no significant difference between GI and GII in ASDAS (3.9±1.3, & 4.1±1.1 respectively).

There was no notable differences between the AS and nr-axSpA neither in BASFI nor in PROMs (p>0.05).

The serum endothelin-1 was significantly elevated in both patients’ groups when compared with controls (GI: 2.3±1.5, GII: 2.05±1.3, controls: 0.76±0.5) with no significant difference between GI and GII (p>0.05). When we measured cIMT we noticed a significant increase in the thickness of cIM of patients in comparison with controls (P < 0.01), while there was no significant difference between the AS and nr-axSpA (p>0.05). We found 6 AS patients had atheromatus plaque, while 4 patients had atheromatus plaque in nr-axSpA group with no significant difference between the 2 groups (p= 0.86)

There was positive correlation between endotheline-1, cIMT and both ASDAS-CRP & BASFI.

Conclusion Axial spondyloarthritis patients (either AS or nr-axSpA) had higher risks for endothelial dysfunction and subclinical atherosclerosis. patients with AS & nr-axSpA shared a comparable disease activity, functional disability and endothelial dysfunction.

References [1]Mease PJ, Heijde DV, Karki C, et al. Characterization of Patients With Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis in the US-Based Corrona Registry. Arthritis Care Res (Hoboken). 2018;70(11):1661-1670.

[2]González Mazón I, Rueda-Gotor J, Ferraz-Amaro I, et al. Subclinical atherosclerotic disease in ankylosing spondylitis and non-radiographic axial spondyloarthritis. A multicenter study on 806 patients. Semin Arthritis Rheum. 2021;51(2):395-403.

[3]Akgul O, Ozgocmen S. Classification criteria for spondyloarthropathies. World J Orthop. 2011 18;2(12):107-15.

Acknowledgements: NIL.

Disclosure of Interests None Declared.