Clinical features and prognostic analysis of very early-onset inflammatory bowel disease

The aim of our study was to summarize the clinical characteristics, treatment responses, and long-term outcomes of children with very early-onset inflammatory bowel disease (VEO-IBD), and to identify factors influencing initial treatment efficacy, first clinical remission, relapse, and treatment withdrawal. This single-center retrospective cohort study with longitudinal follow-up included 84 patients diagnosed with VEO-IBD in the Department of Gastroenterology, Capital Center for Children’s Health, from January 2016 to December 2021. Demographic data, clinical features, genetic results, therapeutic regimens, and outcomes were collected. Logistic regression was performed to evaluate predictors of initial treatment efficacy. Kaplan–Meier analysis was used to estimate cumulative probabilities of first remission, relapse, treatment withdrawal and mortality. Cox proportional hazards models were applied to determine independent factors for remission and relapse. Among 84 patients (47 males, 37 females; median onset age 4.0 months; median follow-up 60.5 months), Crohn’s disease phenotype predominated (64.3%). Fifty-five underwent genetic testing, and 24 carried monogenic variants, including 20 with IL10RA mutations. Overall, 83.3% achieved first clinical remission, including 48.8% who achieved it during initial induction therapy. In multivariate Cox analysis, monogenic mutations were associated with delayed first clinical remission. Relapse occurred in 29.8% of patients, and corticosteroid therapy was associated with increased relapse risk. At the end of follow-up, 82.1% achieved clinical remission, 6.0% remained in mild activity, and 11.9% died. Of the 10 deaths, 7 occurred in patients with monogenic mutations. 9 patients did not receive hematopoietic stem cell transplantation (HSCT) because they were treated before its availability at our center. Following the introduction of HSCT, twelve patients underwent transplantation, including 11 with IL10RA mutations who achieved remission and one patient with a CYBB mutation who died after graft failure at another center. In this single-center cohort Crohn’s disease is the most frequently observed phenotype among children with VEO-IBD. Monogenic variants were frequently detected and may contribute to delayed remission in a subset of patients with VEO-IBD. Corticosteroid treatment is associated with an increased risk of relapse, but should be interpreted cautiously. HSCT may be beneficial in selected monogenic VEO-IBD patients.