E074 Clinical features, disease activity and functional outcome of juvenile-onset, adult-onset and late-onset ankylosing spondylitis: a cross sectional study from India

Abstract Background/Aims Ankylosing spondylitis (AS) or radiographic axial spondyloarthritis (axial SpA) is reported to present with peripheral arthritis, less spinal symptoms, and more radiographic damage in juvenile onset (age at onset ≤16 years) as compared to adult-onset AS(age at onset 45 years). Functional outcome has varied depending on the population studied. In this cross-sectional study we compared clinical features, disease activity, and functional outcome among juvenile-onset AS (JoAS), adult-onset AS(AoAS), late-onset AS (LoAS). Methods Consenting patients fulfilling either the ASAS classification for axial SpA or 1984 modified New York criteria attending SpA clinic were included between May and June 2022. Data was collected by direct patient interview and clinical examination. Data collected: Clinical features, treatment, current disease activity by Bath AS disease activity index (BASDAI), current functional outcome by the Bath Ankylosing Spondylitis Functional Index (BASFI). Disease activity, functional outcome were compared among JoAS, AoAS, and LoAS. Study protocol was approved by the IEC. Results Of 73 patients (61 male), mean age 39.1±12.8 years, 10 (13.7%) were JoAS, 56 (76.7%) and 7 (9.6%) were AoAS and LoAS respectively. Only 30%, 59%, and 57% patients in JoAS, AoAS, and LoAS respectively were employed. There were no differences in the clinical presentation, namely back pain, neck pain, hip involvement, uveitis, and enthesitis among the three groups (Table 1). Majority received conventional-synthetic-DMARDs; only 2(20)%, 8(14.3), and 1(14.3) in the JoAS, AoAS, and LoAS group respectively had ever received TNF-inhibitors. Majority patients in all the groups had active disease (BASDAI4 and ASDAS1.3) and there was also no difference in the disease activity (at enrolment) between the groups. All patients with JoAS were positive for HLA-B27. Mean BASFI was not different between the groups, but poor functional outcome (BASFI 6) was observed in 5/10 (50%), 28/56 (50%), 5/9 (71.4%) patients of JoAS, AoAS, and LoAS respectively. Conclusion In a study involving a homogeneous cohort of Indian AS, there were no marked differences in clinical features, disease activity between JoAS, AoAS, and LoAS. Majority patients have poor functional outcomes which could be a direct effect of poor disease control due to lack of access to TNF inhibitors. Disclosure K. Modadugu: None. M.M. Thabah: None.