THU0511 THE RISK FACTORS OF HIP OSTEOARTHRITIS IN JIA PATIENTS: THE DATA FROM A SINGLE CENTER RETROSPECTIVE CONTINUOUS STUDY
Authors: L. Sorokina, R. Raupov, I. Avrusin, M. Gharabaghtsyan, N. Garipova, S. Khrypov, M. Dubko, L. Snegireva, T. Likhacheva, A. Santimov, E. Gaidar, E. Isupova, I. Chikova, T. Kornishina, V. Masalova, M. Kostik
Journal: Annals of the Rheumatic Diseases (2020)

Background: Hip osteoarthritis (HOA) is a severe irreversible complication of patients with juvenile idiopathic arthritis (JIA) leads to intensive pain, disability and required total hip arthroplasty (THA) in childhood or in the young adults. Objectives: the aim of our study was to evaluate risk factors of HOA in JIA patients. Methods: we analyzed 753 patients with JIA for last 10 years. In each patient we observed if the HOA developed or no. We evaluated the main clinical JIA measurements, such a JIA category, CRP, ESR, WBC, PLT, active joints, initial or delayed hip involvement, ANA, HLA B27, onset age, JIA duration, time before HOA and before THA, bone metabolic markers, treatment, particularly glucocorticosteroids (GCS), their cumulative doses, route of administration (oral, intra-articular, pulse therapy). HOA was confirmed with radiological assessment (MRI and CT). For comparison analysis used nonparamentric statistics. Each possible variable was evaluated with univariate regression analysis and further multiple regression analysis was applied. Results: the comparative study between 2 groups shown in the table 1. HOA was detected in 48 (6.4%), in oligoarthritis-0%, in polyarthritis - 4.9%, in psoriatic arthritis - 5.0%, in enthesitis-related arthritis -11.8%, in systemic arthritis 19% (p=0.0000001), THA was performed in 16 (2.1%). Hip involvement at onset of JIA was similar in both groups (49.5% vs 41.7%, p=0.367). Table 1. Characteristics of JIA patients, depends on HOA development. Parameter HOA (n=48) No HOA (n=705) p Onset age, y 8.0 (4.0; 12.5) 5.9 (3.0; 10.7) 0.045 HLA B27, n (%) 13/25 (52.0) 88/283 (31.1) 0.033 JIA duration, y 7.5 (3.2; 12.1) 4.2 (1.8; 7.2) 0.00007 CRP, mg\l 2.8 (0.8; 20.9) 1.3 (0; 7.1) 0.006 Active joints, n 11.0 (6.0; 27.0) 6.0 (3.0; 12.0) 0.000001 Oral GCS, n(%) 21 (43.8) 131/704 (18.6) 0.00003 GCS pulse-therapy, n (%) 21 (43.8) 114/702 (16.2) 0.000002 GCS, cumulative doses, mg 5000 (3000; 16000) 2000 (1000; 4000) 0.001 Biologics, n (%) 43 (89.6) 308 (43.7) 0.0000001 Remission, n (%) 24 (50.0) 461 (65.4) 0.03 Time, before remission, y 7.4 (3.9; 12.3) 3.0 (1.4; 6.2) 0.0000001 Alkaline phosphatase, U\l 129.3 (84; 244) 223 (147; 386) 0.00001 Delayed hip involvement, n (%) 28 (58.3) 24/87 (27.6) 0.00004 We calculated cut-off and OR of variables, associated with HOA development (table 2). After selection of 26 clinically meaningful and statistical significant risk factors only 22 pass the univariate regression analysis. In multiple regression analysis the main independent risk factors of HOA development were: HLA b27 (p=0.001), oral GCS/pulse therapy GCS (p=0.03) and alkaline phosphatase≤165 U/l (p=0.00006). Table 2. Cutt-offs, odds ratio for HOA risk factors in JIA patients. Parameter Se Sp OR (95%CI) p Active joints &gt; 4 89,6 42,0 6,2 (2,4-15,9) 0,000002 Alkaline phosphatase ≤ 165 U/l 65,9 70,8 4,7 (2,4-9,2) 0,000001 GCS &gt; 2700 mg 82,6 58,1 6,6 (2,1-20,6) 0,0004 Time before remission&gt;5 years 66,7 78,9 7,5 (3,1-18,0) 0,0000001 Time before biologics &gt;7,8 years 44,2 86,7 5,2 (2,6-10,2) 0,0000001 Conclusion: the main risk factors of HOA were increased inflammatory activity, systemic arthritis, HLA B27, systemic corticosteroids, delayed remission and biologics, decreased bone metabolism. Delayed hip involvement underline the possible non-inflammatory mechanism of HOA, such as avascular necrosis. Disclosure of Interests: None declared