BackgroundChildren and adolescents with juvenile idiopathic arthritis (JIA) may suffer from disability and disease-related damage. This study aimed to investigate the prevalence of disability and damage, and identify the factors associated with articular and extra-articular damage in children and adolescents with JIA in a resource-restricted setting in Thailand.MethodsThis cross-sectional study enrolled JIA patients during June 2019-June 2021. Disability was assessed using the Child Health Assessment Questionnaire (CHAQ) and Steinbrocker classification criteria. Damage was evaluated using the Juvenile Arthritis Damage Index (JADI) and the modified-JADI (mJADI) tools.ResultsThere were 101 patients (50.5% female) with median age of 11.8 years. Median disease duration was 32.7 months. Enthesitis-related arthritis (ERA) was the most common subtype (33.7%), followed by systemic JIA (25.7%). Thirty-three (32.7%) patients had delayed diagnosis ≥ 6 months. Moderate to severe disability was found in 20 (19.8%) patients. Patients with Steinbrocker functional classification > class I were seen in 17.9%. Thirty-seven (36.6%) patients had articular damage. Extra-articular complications were observed in 24.8%. Growth failure and striae were the most common complications in 7.8%. Leg-length discrepancy was documented in 5.0%. Ocular damage was found in 1 patient with ERA. Multivariable logistic regression analysis revealed Steinbrocker functional classification > class I (aOR: 18.1, 95% CI: 3.9–84.6;p< 0.001), delayed diagnosis ≥ 6 months (aOR: 8.5, 95%CI: 2.7–27.0;p< 0.001), and ERA (aOR: 5.7, 95%CI: 1.8–18.3;p= 0.004) as independent predictors of articular damage. Systemic corticosteroids use was the independent predictor of extra-articular damage (aOR: 3.8, 95%CI: 1.3–11.1;p= 0.013).ConclusionsDisability and disease-related damage was identified in one-fifth and one-third of JIA patients. Early detection and treatment are essential for preventing permanent damage.