AB0498 INFLUENCE OF SYNOVITIS OF THE HIP JOINTS ON X-RAY PROGRESSION OF COXITIS IN AXIAL SPONDYLOARTHRITIS. RESULTS OF TWO YEARS FOLLOW-UP
Authors: E. Agafonova, S. Erdes, T. Dubinina, A. Demina, D. Rumiantceva, A. Smirnov
Journal: Annals of the Rheumatic Diseases (2021)

Background: Almost half of patients with axial spondyloarthritis (axSpA) in Russia have hip joint lesions (HJ), but only in 7% of cases it becomes so severe and requires arthroplasty. The causes and rates of progression of coxitis have not been studied. Objectives: To assess the relationship between disease activity and the sonographic synovitis of the hip joint with the progression of X-ray coxitis in patients with axSpA with a 2-year follow-up. Methods: The study included 77 patients (mean age 28 ± 5.92 years) with axSpA (ASAS criteria 2009), who were followed up for at least 2 years. Among them, AS (mNY criteria, 1984) had 66 (86%) patients, and nonradiographic axSpA - 11 (14%). The median duration of the disease was 30 [3–60] months, BASDAI - 4.5 [3.2; 5.9], BASFI - 2.4 [0.9; 4.8]. All patients underwent clinical examination, X-ray and ultrasound investigation of the hip joint during the monitoring period. For ultrasound, coxitis was considered an increase in the cervical-capsular distance (CCD) of more than 7 mm. An increase in BASRI hip by 1 stage in 2 years was considered as progression of radiographic coxitis (PRC). Results: At the time of enrollment, 66 (86%) patients out of 77 patients had pain in the hip joint, and after 24 months - 48 (62%) (p&gt; 0.05). At the time of inclusion, the median pain in the hip joint was 4 [2; 5]; severe pain (≥4.0) had 38% of patients. The median CCD at the time of inclusion was 7.3 [6.4; 8.2] mm, and two years later 6.6 [5.9; 8.2] mm (p&gt; 0.05). At the sonographic examination at the beginning of follow-up 63 (82.0%) patients had coxitis, and after 2 years - 45 (58%) (p &lt;0.05). X-ray coxitis at the time of inclusion was present in 19 (25%) patients, and after 2 years - in 48 (62%) (p &lt;0.05). Depending on the presence or absence of PRC after 2 years, the patients were divided into 2 groups (Table 1). All patients with PRC at the start of the study had sonographically diagnosed synovitis, while among those without progression, only half of them; relative risk of X-ray progression in the presence of ultrasound of synovitis (RR) = 10.5 (p &lt;0.05). The groups did not differ in terms of activity indicators and the presence of extra-axial manifestations. Table 1. Characteristics of patients with axSpA at the time of inclusion in the study who had PRC after 24 months of observation. Parametrs ΔBASRI hip=0 n=33 ΔBASRI hip &gt;0 n = 44 p Sex (m/w), n 22/11 32/12 &gt;0,05 The duration of the disease, m., Мe [25;75‰] 36 [19;132] 48 [24;84] &gt;0,05 Age, years, Мe [25;75 ‰] 30 [26;34] 28 [24;34] &gt;0,05 BASDAI, Мe [25;75 ‰] 4,3 [3,1;5,8] 4,7 [3,8;6,3] &gt;0,05 BASFI, Мe [25;75 ‰] 3,4 [0,6;5,6] 2,1 [1,1;4,2] &gt;0,05 ASDAS (SRP), Мe [25;75 ‰] 2,6 [1,6;3,9] 3,2 [2,3;4,2] &gt;0,05 ESR, mm/h, Мe [25;75 ‰] 15 [7;30] 23,0 [12;35] &gt;0,05 SRP, mg/l, Мe [25;75 ‰] 12,8 [1,8;31,0] 17,8 [5,6; 50,3] &gt;0,05 Peripheral arthritis, n % 26 (79%) 32 (73%) &gt;0,05 US synovitis n% 19 (58%) 44 (100%) &lt;0,05* Pain in HJ n% 28 (85%) 38 (86%) &gt;0,05 Conclusion: X-ray progression of coxitis is associated with ultrasound synovitis and does not depend on the activity of the disease. Disclosure of Interests: None declared.