High and low body mass index may predict severe disease course in children with inflammatory bowel disease

Objectives: Inflammatory bowel disease (IBD) has been historically associated with underweight and malnutrition. The impact of both underweight and obesity on the clinical course of IBD in adults is controversial. This study described the association between body mass index (BMI) at diagnosis to disease course in children with IBD.Methods: We reviewed the medical records of children with IBD from the database of the Dana-Dwek' Children's Hospital between 2010 and 2016. Demographic and anthropometric data were collected as were disease characteristics, course and therapy. Patients were categorized in quartiles according to BMI percentiles at diagnosis (Q1-Q4).Results: Of 100 children who were identified, 62 had Crohn's disease (CD) and 38 had ulcerative colitis (UC). The median age (interquartile range, IQR) at diagnosis was 13.7 (range 11.9-15.2) years. The median (IQR) follow-up was 2.1 (1.2-3.8) years. At diagnosis, 46 children (46%) were in Q1, 20 (20%) in Q2, 19 (19%) in Q3 and 15 (15%) in Q4. Prolonged time to diagnosis was associated with BMI in Q1 and Q4, as well as high disease activity at diagnosis (p<.001). In a multivariate analysis, BMI in the lower and upper quartiles was associated with disease exacerbation (HR 3.212 and 4.651, respectively, p=.016) and anti-tumor necrosis factor (TNF) therapy (HR 4.489 and 3.972, respectively, p=.021).Conclusions: BMI in the lower and upper quartiles was associated with more severe disease course in children with IBD. BMI may serve as a simple and highly accessible predictor of pediatric IBD course and prognosis.