HIP INVOLVEMENT IS A MORE FREQUENT COMPLICATION IN ENTHESITIS-RELATED ARTHRITIS COMPARING TO THE ADULT SPONDYLARTHRITIS

BackgroundThe hip disease develops in 30% to 50% of children with juvenile idiopathic arthritis (JIA) and is associated with poor outcomes and functional impairment. The coxitis in enthesitis-related arthritis (ERA or juvenile-onset spondyloarthritis) patients was frequent but weakly studied.ObjectivesTo assess the occurrence of coxitis in patients with ERA and compare it to that of older patients with spondyloarthritis (SpA).MethodsWe conducted a retrospective comparative study including patients with ERA and adult spondyloarthritis patients.The first group included patients under 16 years old fulfilling the International League of Associations for Rheumatology (ILAR). The second group of patients fulfilled the Assessment of SpondyloArthritis International Society (ASAS) 2009 criteria.We studied the socio-demographic characteristics of both groups, the hip involvement occurrence, and the treatment modalities.Quality of life was appraised by the Study 36-item Short-Form Health Survey (SF-36) and the Ankylosing spondylitis quality of life test (ASQOL).ResultsForty ERA (mean age= 25,3 ± 10,15) patients and 134 SpA (mean age=37,96±11,77) patients were enrolled. Seventeen ERA patients (42,5%) had coxitis at recruitment compared to 28 SpA patients (20,9%), p=0,06. More than half of the ERA patients were positive to HLAb27, compared to the SpA group (44,7%) without reaching a significant threshold, p=0,07. The mean delay of coxitis onset in ERA patients was 4,66 ± 8,46 years, and was 5,65 ± 6,85 years in SpA patients, with no significant difference between the two groups (p=0,527). There was no difference between the two groups for the coxitis being unilateral or bilateral (p=0,272 and 0,169 respectively). Regarding the treatment approach, local therapy was proposed to 11 patients in the ERA group and 13 patients in the SpA group (p=0,07), with synoviorthesis being the most common therapy. Total hip replacement was done in 8 ERA patients (of which seven were bilateral) and in 17 SpA patients (of which ten were bilateral), without reaching the significant threshold (p=0,858). There was no significant difference between the two groups on the period when the total hip replacement was done (p=0,925). Quality of life assessed by the ASQOL and the SF-36 was comparable between the two groups (p=0,666 and 0,326; respectively).ConclusionOur study shows the high prevalence of hip involvement in the juvenile group of SpA. This complication occurs within the five years of disease outcomes and constitutes a turning point in their lives.Disclosure of InterestsNone declared