Supplementary Material for: Evolution of growth following anti-TNF-α therapy in paediatric Crohn’s disease: data from the Swiss IBD Cohort Study

Objectives: Up to 85% of paediatric patients affected by Crohn’s disease experience growth failure. This study aims to elucidate the effects of anti-TNF biologics on patient growth.
Methods: This retrospective analysis examined height, height velocity and weight in paediatric 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 paediatric 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.
Conclusions: Our findings indicate that anti-TNF biologics are associated with significant short-term height and long-term weight gains in paediatric patients with Crohn’s disease, similar to those observed with immunomodulators.