Evolution of Growth following Anti-Tumor Necrosis Factor-α Therapy in Paediatric Crohn's Disease: Data from the Swiss IBD Cohort Study.

Introduction
Up to 85% of pediatric patients affected by Crohn's disease experience growth failure. This study aims to elucidate the effects of anti-tumor necrosis factor (TNF) biologics on patient growth.Methods
This retrospective analysis examined height, height velocity and weight in pediatric patients with Crohn's disease from the Swiss Inflammatory Bowel Disease Cohort Study between 2007 and 2020 (n = 97). Z-scores were determined according to age and gender of a healthy pediatric population. Growth of patients treated with anti-TNF biologics and immunomodulators was analyzed by linear regression over 5 years and compared within each subgroup by paired Student t tests 1 year (T1), 2 years (T2), and 5 years (T5) after treatment initiation.Results
Mean height and weight z-scores at diagnosis were -0.3 ± 1.3 and -1.0 ± 1.6, respectively (age at diagnosis 11.1 ± 2.7 years, 52.0% male). Initial treatment was led by azathioprine (58.3%) and infliximab (19.8%). Patients treated with biologics exhibited significant height increase at T1 (p = 0.022), with an overall flat height evolution (y = 0.00x - 0.31), whereas significant weight increase was maintained at T5 (p = 0.0005, y = 0.13x - 0.50). Patients on immunomodulators showed a height increase (y = 0.15x - 0.20) and a significant weight increase at T2 (p = 0.0047, y = 0.10x - 0.41). Height velocity z-scores showed a significant increase across both genders. Factors contributing to a decreased height z-score included male sex, age 10 and below at diagnosis, a concomitant corticosteroid treatment and a top-down treatment strategy.Conclusion
Our findings indicate that anti-TNF biologics are associated with significant short-term height and long-term weight gains in pediatric patients with Crohn's disease, similar to those observed with immunomodulators.