Juvenile Idiopathic Arthritis in South Australia

Abstract

Background: Juvenile Idiopathic Arthritis (JIA) is a chronic rheumatic disease that shows variation in subtype distribution by geographic regions. The aim of this study was to create a JIA registry, which could describe the epidemiology and characteristics of JIA patients in South Australia (SA).Methods: Prospectively collected data from JIA patients at the Women’s and Children’s Hospital in Adelaide, between August 2019 and March 2020 were reported. All children and young people diagnosed with JIA according to the International League of Associations for Rheumatology (ILAR) classification criteria were eligible for inclusion. Data including demographics, complications/comorbidities, medications, disease activity as well as patient-reported data using Childhood Health Assessment Questionnaire (CHAQ) were documented. Non-identified data were extracted from this registry and utilised in descriptive analysis and comparative studies.Results: There are currently n=112 JIA patients in this registry, including n=11 incident cases (9.8%), with a predominance of female (n=75, 67.0%). The median disease duration was 3.6 years (interquartile range 1.3-7.6). The most common subtype was persistent oligoarthritis (n=35/112, 31.3%), followed by rheumatoid factor-negative polyarthritis (n=32/112, 28.6%), extended oligoarthritis (n=23/112, 20.5%), enthesitis-related arthritis (ERA; n=12/112, 10.7%), systemic onset arthritis (n=5/112, 4.5%), rheumatoid factor-positive polyarthritis (n=3/112, 2.7%) and psoriatic arthritis (n=2/112, 1.8%). Complications were documented in n=40/112 (35.7%) patients, with n=21/94 (22.3%) observed to have uveitis, and musculoskeletal complications observed in n=10/112 (8.9%). Methotrexate intolerance was present in n=10/79 (12.7%) patients. Forty-nine out of 112 (43.8%) patients had at least one comorbidity, with anxiety/depression (n=5/112, 4.5%) and asthma (n=5/112, 4.5%) being the most common. Around half of patients (n=52/112, 46.4%) had clinically inactive disease at enrolment and most (n=85/112, 75.9%) reported no to low functional disability. Non-steroidal anti-inflammatory drugs have been almost universally used (n=100/112, 89.3%), and n=26/112 (23.2%) have received treatment with biologics.Conclusions: In this JIA registry study, we found that the JIA cohort in SA is female-dominated with persistent oligoarthritis as the most common subtype, consistent with other studies. Most patients have good disease control and report no or mild disability. Further longitudinal work will add to the current description of our JIA cohort and assist improvement of clinical care.