POS1008 FACTORS ASSOCIATED WITH HIP INVOLVEMENT AND ITS IMPACT ON TREATMENT DECISION IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS; TREASURE EXPERIENCE

Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease affecting sacroiliac joints, spine and peripheral joints. In addition to spinal and peripheral manifestations, root joints (hip or sholder) involvement may also develop. Hip involvement is reported 24-36% in patients with Ankylosing Spondylitis (AS) by clinical evaluation of the rheumatologists. However, there is limited data regarding the factors related with the presence of hip involvement and treatment preference in patients with axSpA. The aim of this study was to evaluate the factors/covariates associated with the hip involvement and its impact on the treatment preferences in patients with axSpA patients who initiated their first biologic therapy. In total, 1600 axSpA patients who initiated his/her first biologic were included in the study. The data for the current study was obtained from the TReasure web-based registry. Baseline demographics and disease related characteristics were collected. Characteristics and treatment preference of patients with and without hip involvement were compared. The factors/covariates associated with the presence of hip involvement were evaluated by regression analysis. Hip involvement was reported in 375 patients (23.4%). Patients with hip involvement were more common male patients in addition they had lower education level, lower BMI and more frequent HLA-B27 positivity as well as longer disease duration. Hip involvement was more frequent in patients with r-axSpA than patients with nr-axSpA. We found lower percentages of peripheral arthritis, enthesitis and dactylitis, higher BASFI or ASDAS-CRP scores, higher serum CRP levels and ESR values in patients with hip involvement. Moreover, patients with hip involvement had less frequently SpA-related family history ( Table 1 ). When we analyzed patients according to age at diagnosis (≥ 16 years, <16 years) we found that patients with hip involvement were more common in juvenile onset axSpA group. In multivariate analysis, we found that lower education level (OR:2.029, 95%CI:[1.461-2.817]; p<0.001), diagnosis (r-axSpA) (OR:0.532, 95%CI:[0.337-0.839]; p=0.007) longer disease duration (OR:1.002, 95%CI:[1.001-1.004]; p=0.002), lower percentages of enthesitis (OR:0.405, 95%CI:[0.283-0.579]; p<0.001), higher BASFI scores (OR:1.086, 95%CI:[1.025-1.151]; p=0.005) and serum CRP levels (OR:1.005, 95%CI:[1.001-1.010]; p=0.019) absence of SpA family history (OR:0.713, 95%CI:[0.528]; p=0.027) were associated with hip involvement. Table 1Characteristics of patients with axSpAAll patients (n=1600)Hip involvement (+) (n=375)Hip involvement (-) (n=1225)P*Juvenile (<16 years) onset, n(%)30 (1.9)12 (3.2)18 (1.5)0.031Male sex, n(%)940 (58.8)255 (68)685 (55.9)<0.001HLA-B27 positivity, n(%)605 (55)178 (62.7)427 (52.3)0.002BMI, kg/m2mean (SD)27.2 (5.2)26.7 (5.0)27.4 (5.2)0.023Education duration (≤12 years), n (%)1014 (65.9)263 (71.3)751 (64.2)0.013mNY positivity, n(%)1276 (79.8)338 (90.1)938 (76.6)<0.001Disease duration (month) median (IQR 25-75)82 (36-151)111 (52-200)74.5 (32-139)<0.001SPA-related family history, n (%)544 (34)110 (29.3)434 (35.4)0.029BASFI, mean (SD)3.9 (2.5)4.3 (2.1)3.8 (2.7)0.007ASDAS-CRP, mean (SD)3.1 (1.5)3.7 (1.4)2.9 (1.5)<0.001CRP (mg/dl), median (IQR 25-75)8.6 (3-21)12.0 (4.0-27.9)7.6 (2.5-19)<0.001 When we compared the treatment patterns of axSpA patients with and without hip involvement, we found that the percentages of NSAID as well as csDMARD use were similar in groups. However, the percentages of patients who were prescribed etanercept were higher in axSpA patients with hip involvement (p<0.001). In addition to inflammation and function, hip involvement seems to be related with diagnosis (r-axSpA), education level and absence of SpA family history. Moreover, enthesitis may not accompany hip involvement. None declared