[Epidemiologic profile of juvenile-onset compared to adult-onset spondyloarthritis in a large Brazilian cohort]. / Perfil epidemiológico da espondiloartrite de início juvenil comparada com a espondiloartrite de início na vida adulta em uma grande coorte brasileira.

OBJECTIVE: To analyze the clinical and epidemiologic characteristics of juvenile-onset spondyloarthritis (SpA) (< 16 years) and compare them with a group of adult-onset (≥ 16 years) SpA patients. PATIENTS AND METHODS: Prospective, observational and multicentric cohort with 1,424 patients with the diagnosis of SpA according to the European Spondyloarthropathy Study Group (ESSG) submitted to a common protocol of investigation and recruited in 29 reference centers participants of the Brazilian Registry of Spondyloarthritis (RBE - Registro Brasileiro de Espondiloartrites). Patients were divided in two groups: age at onset<16 years (JOSpA group) and age at onset ≥ 16 years (AOSpA group). RESULTS: Among the 1,424 patients, 235 presented disease onset before 16 years (16.5%). The clinical and epidemiologic variables associated with JOSpA were male gender (p<0.001), lower limb arthritis (p=0.001), enthesitis (p=0.008), anterior uveitis (p=0.041) and positive HLA-B27 (p=0.017), associated with lower scores of disease activity (Bath Ankylosing Spondylitis Disease Activity Index - BASDAI; p=0.007) and functionality (Bath Ankylosing Spondylitis Functional Index - BASFI; p=0.036). Cutaneous psoriasis (p<0.001), inflammatory bowel disease (p=0.023), dactylitis (p=0.024) and nail involvement (p=0.004) were more frequent in patients with adult-onset SpA. CONCLUSIONS: Patients with JOSpA in this large Brazilian cohort were characterized predominantly by male gender, peripheral involvement (arthritis and enthesitis), positive HLA-B27 and lower disease scores.