P020 The male gender predicts the hip involvement among JIA patients

Abstract Background Juvenile idiopathic arthritis (JIA) represents a heterogeneous group of chronic arthritides that affect children aged 16 years and under. Regardless of the clinical presentation, hip involvement ranges between 20% to50% of cases [1]. The aim of the present study was to examine the role of gender and disease onset in coxitis involvement. Methods We conducted a cross-sectional study including children with JIA according to the International League of Associations for Rheumatology (ILAR)). Transcribed data included age, sex and the characteristics of the disease (subtype of JIA, disease duration). Regarding coxitis, we collected radiographs, ultrasound (US) and magnetic resonance imaging (MRI) of the hip when performed. Coxitis was defined by clinical (limited range of motion) and/or radiographic findings (destruction, synovitis, bone marrow oedema). We divided patients into two groups: G1: presence of coxitis and G2: absence of coxitis. Results The study included 62 patients with a male perdominance: sex ratio was 2.3. The mean age of onset of the disease was 11.4 years [3–16]. The frequency of each JIA subset was as follows: polyarticular with rheumatoid factor (n = 2), polyarticular without rheumatoid factor (n = 4), systemic (n = 1), enthesitis-related arthritis (n = 44), oligoarthritis (n = 8), psoriatic arthritis (n = 3). A Hip involvement was reported in 71% of cases and was bilateral in 81% of patients. Coxitis was not correlated with the disease duration (P = 0.7). A positive correlation was found between the age of onset of the disease and the presence of coxitis (12.2 vs 9.6, P = 0.005). However, hip involvement was higher among males without significant difference (76.7% vs 58%, P = 0.132). Conclusion Unlike the literature data, our study showed a high frequency of hip involvement in Tunisian children with JIA. We found an association between the male gender and coxitis involvement without significant difference. However, coxitis was more frequent in later onset of the disease.