The Impact of Sarcopenia on Clinical Outcomes in Pediatric Crohn’s Disease

Background The effect of sarcopenia on clinical outcomes in children with Crohn's disease (CD) is unknown. We investigated whether sarcopenia at the diagnosis impacts the outcomes of children with CD. Methods This was a retrospective, single-center, case-control study of newly diagnosed children with CD undergoing magnetic resonance (MR) within 1 month from the diagnosis, from 2011 to 2022. Sarcopenia was assessed by measuring total psoas muscle area (tPMA) at L3-L4 level on the MR and defined as z-score values <= 2 SDs. Children with and without sarcopenia were compared for the risk of disease flares, CD-related hospitalization, complications, need for step-up treatment, and courses of steroids over a 2-year follow-up. Results Seventy-eight children were included (median age 10.7 years), 46 (59%) with sarcopenia and 32 (41%) without. The risk of clinical relapse was higher in patients with sarcopenia at 6 [19.5% vs 3%, odds ratio (OR) 7.5 (95% CI, 1.5-85)] and 12 months [30% vs 6%, OR 6.5 (95% CI, 1.4-30.4)]. Kaplan-Meier analysis showed lower survival free from relapses in children with sarcopenia (log rank P = .01, hazard ratio 2.7, 95% CI, 1.4-4.5). Multivariate analysis identified sarcopenia as independent predictors of clinical relapses (OR 1.7, 95% CI, 1-3.1, P = .045). No other independent predictor of unfavorable outcome was detected. Conclusions The presence of sarcopenia at the diagnosis increases the risk of clinical relapses in the first year of diagnosis. Magnetic resonance evaluation of the tPMA could therefore help identify children at higher risk of worse outcomes.