AB1126 No radiographic wrist damage after targeted treatment in juvenile idiopathic arthritis

BackgroundJuvenile idiopathic arthritis (JIA) is characterised by chronic inflammation of the joints which can lead to structural bone damage.ObjectivesThe objective of this study was to evaluate the response of new onset JIA patients to an early targeted treatment by conventional radiography.MethodsJIA patients participating in the BeSt for Kids study (NTR 1574) were eligible in case of wrist involvement at inclusion and if conventional radiographs were available at baseline or within 6 months before or after study inclusion. Follow-up radiographs of hands and wrists after 12–36 months were available for comparison. Radiographic bone damage as reflected by carpal length was assessed using the Poznanski score1, providing ‘Z’ as indication of the deviation from a healthy population as measured by radiometacarpal length relative to the second metacarpal length (RM/M2). BoneXpert method2 was used to automatically determine bone age and bone mineral density (BMD) of the wrist.ResultsForty JIA (27 female) patients were evaluated for Poznanski score and BMD (mean age 7.2±3.4 years), 26 patients (15 female) were evaluated for bone age (mean age 9.3±2.2 years). Assessed by the mean Z-score of RM/M2, we did not detect wrist damage at baseline nor at follow-up. Assessed by the mean Z-score of the bone age, we did not detect deviating bone age at baseline nor at follow-up. At baseline BMD was significantly diminished compared to healthy controls (Z-score −0.71, 95% CI=−1.12 to −0.30). BMD at follow-up improved significantly (Z-score −0.44, 95% CI=−0.75 to −0.12, p=0.032). Results are summarised in table 1.ConclusionsIn this cohort of JIA patients treated early and targeted at inactive disease, we have detected no radiographic wrist damage at baseline or follow-up as detected by Poznanski score. BMD was significantly diminished at baseline but improved significantly after follow-up.References[1] Poznanski AK, Hernandez RJ, Guire KE, Bereza UL, Garn SM. Carpal length in children – a useful measurement in the diagnosis of rheumatoid arthritis and some congenital malformation syndromes. Radiology1978;129:661–8. [2] Anink J, Nusman CM, van Suijlekom-Smit LW, van Rijn RR, Maas M, van Rossum MA. Automated determination of bone age and bone mineral density in patients with juvenile idiopathic arthritis: a feasibility study. Arthritis Res Ther 2014;16:424.Disclosure of InterestNone declared