POS0136 IS GROWTH ADVERSELY AFFECTED IN CHILDREN WITH CHRONIC NON-BACTERIAL OSTEOMYELITIS?
Authors: P. Miettunen, L. Carlini, A. Insalaco, J. Anton, J. Brunner, E. Legger, M. Cattalini, E. Hoppenreijs, M. Alessio, E. Mosci, R. Caorsi, N. Ruperto, M. Gattorno
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory disease with remitting and recurring bone inflammation. There is no uniformly effective treatment. It is not known if CNO has an adverse effect on growth in pediatric population. <h3>Objectives:</h3> To obtain longitudinal data on growth in a large-scale multinational prospective cohort of pediatric CNO patients with data from EUROFEVER registry. <h3>Methods:</h3> Inclusion criteria were children with CNO with anthropometric data available during the first 2 years after diagnosis. Data was collected for demographics, treatment, potential vertebral fractures and growth, including serial heights, weights, and body mass index (BMI). Statistical analysis included descriptive statistic and Cox multivariate regression model. <h3>Results:</h3> A total of 237/573 (41.4%) children ≤ 18 years with CNO from the EUROFEVER registry met the inclusion criteria. The median [IQR] age at baseline (n= 237) was 10.07 years [7.94; 11.81] with median baseline height z-score of -0.08 [-0.72; 0.83] and median BMI z-score of 0.8 [-0.43; 2.1]. Longitudinal growth data was available for 125/237 (52.7%) patients, with median follow-up of 25.4 months [12.4; 44.1]. Treatment in this longitudinal cohort included NSAIDS (n=117, 93.6%), conventional synthetic DMARDS (n=38, 30.4%), biologic DMARDS (n=30, 24%), bisphosphonates (n=12, 9.6^0, and glucocorticoids (n=34, 27.2%). The median [IQR] duration of glucocorticoid treatment was 70 [30;168] days; the median prednisone equivalent dose was 0.55 [0.27;1.01] mg/kg/day. Active disease was present in 85.6% of patients during the final 3 months of follow-up. No spinal fractures were present at baseline nor at the final follow-up. There was no difference between baseline height and BMI between 125 patients with longitudinal data and 112 patients with baseline data only. In <b>the longitudinal cohort</b>, the median height z-scores at baseline and at final follow-up (-0.1 [-0.7; 0.8] <i>vs</i>. -0.02 [-0.78; 0.59]) were similar. Similarly, the median baseline and final follow-up BMI z-scores were not statistically different (0.83 [-0.27; 2.13]) <i>vs.</i> 0.79 [-0.08; 1.96]). However, growth failure, defined as height deflection (change in height z-score less than -0.25/year) was present in 24.8% of patients, with no gender difference, with no additional effect from corticosteroids. <h3>Conclusion:</h3> CNO had no significant impact on growth in affected children at baseline. Height deflection at final follow-up was present in 24.8 % of patients. No spinal fractures were present to account for poor linear growth. Our results suggest that recurring episodes of inflammation can adversely affect linear growth during the first 2 years after diagnosis. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> Paivi Miettunen: None declared, Luca Carlini: None declared, Antonella Insalaco: None declared, Jordi Anton: None declared, Juergen Brunner: None declared, Elizabeth Legger: None declared, Marco Cattalini: None declared, Esther Hoppenreijs: None declared, Maria Alessio: None declared, Eugenia Mosci: None declared, Roberta Caorsi: None declared, Nicolino Ruperto Abbvie, Aclaris, Amgen, AstraZeneca, Aurinia, BMS, Boehringer Ingelheim, Eli Lilly, Galapagos, Guidepoint, Janssen, Novartis, Pfizer, Sanofi, Abbvie, Aclaris, Amgen, AstraZeneca, Aurinia, BMS, Boehringer Ingelheim, Eli Lilly, Galapagos, Guidepoint, Janssen, Novartis, Pfizer, Sanofi, Marco Gattorno: None declared.