PO:30:157 | Radiographic assessment of measurable osteoarticular damage in juvenile idiopathic arthritis (JIA) patients transitioning to adult care

Serena Pastore⁴, Marta Klanmjsceck³, Andrea Guiotto¹, Laura De Nardi^5|6, Alessia Pin⁴, Lorenzo Cereser^1|2, Andrea Taddio^3|4, Luisa Occhipinti¹, Luca Quartuccio^1|2, Alberto Tommasini^3|4, Alen Zabotti² | ¹Università degli Studi di Udine Udine, Italy; ²Ospedale Santa Maria della Misericordia Udine, Italy; ³Università degli Studi di Trieste Trieste, Italy; ⁴IRCCS Materno Infantile Burlo Garofolo Trieste, Italy; ⁵Università Tor Vergata Roma, Italy; ⁶Ospedale Pediatrico Bambino Gesù Roma, Italy

Objectives. Juvenile idiopathic arthritis (JIA) is the most common pediatric rheumatic disease, causing chronic jointinflammation and potential damage. While conventional radiography is the gold standard for detecting structural damage,interpreting scans in children is challenging due to skeletal immaturity. Routine radiographic monitoring is less common in JIA than in adult rheumatoid arthritis, partly based on the belief that damage is infrequent. However, recent studies indicate significant damage rates, particularly in certain JIA subtypes. Evidence suggests anti-TNF agents may better prevent damage than methotrexate (MTX) in polyarticular cases. Critically, joint outcomes in JIA patients transitioning to adult rheumatology care have not been quantified. This study's primary aim was to quantify radiographic damage in a cohort of JIA patients after physeal closure and assess associations with childhood treatments. The secondary aim was to explore correlations between radiographic damage and clinical/laboratory variables.

Methods. This cross-sectional study, conducted from January to October 2023, included 30 patients with JIA (83.3%female) transitioning to adult care. Hands/wrists, knees, and pelvis radiographs were assessed using Larsen andmodified Sharp/Van der Heijde scores. Clinical, laboratory, and treatment data were collected retrospectively. TheJuvenile Arthritis Damage Index (JADI) was also applied. Fisher's test and Pearson correlation in R explored potentialassociations.

Results. No significant clinical differences were found between patients with and without radiographic damage,except forhigher clinical hip involvement in the damaged group. Osteophytosis (71.4%) was the most common radiographic finding,followed by joint space narrowing (28.6%) and erosions/juxta-articular osteoporosis (14.3%). Of 14 patients with radiographic damage, 6 had positive scores on Larsen or Sharp/Van der Heijde scores. The hips were the mostfrequently affected joints on radiographs (9 patients), followed by the carpus (6) and knees (3). No substantial link wasfound between radiographic damage and MTX therapy duration, treatment with biologics, previous arthrocentesis, or cumulative months of active illness, but there was a mild inverse correlation with the JADI-A score.

Conclusions. This study found that up to 50% of patients with JIA exhibit radiographic damage after physeal closure.Notably, many presented only with osteophytosis, often missed by standard damage scores like Larsen and Sharp/Van der Heijde. Furthermore, the observed inverse correlation between JADI-A and the measures of radiographic damage underscores the poor agreement between different assessment tools. This highlights the limitations of current scoring methods and the need for revised approaches, although the clinical significance of osteophytosis, potentially reflectingmechanical stress rather than inflammation, warrants further study.