Impact of disease activity on resting energy expenditure in children with inflammatory bowel disease.

BACKGROUND AND AIMS: Exclusive enteral nutrition is used as primary therapy in Crohn's disease. Nutrition support is frequently required in children with both Crohn's disease and Ulcerative Colitis when acutely unwell and during periods of recovery. There is considerable controversy about nutritional needs during phases of active and inactive disease. It is, for example, often assumed that in acute illness a child requires increased nutritional support however the precise relationship between illness severity and energy expenditure is uncertain. This study explores the relationship between disease activity and resting energy expenditure (REE) in children with inflammatory bowel disease. METHODS: Patients were recruited from the regional paediatric gastroenterology unit at Southampton University Hospitals NHS Trust. Disease activity was assessed using standard scoring systems (Paediatric Crohn's Disease Activity Index; Simple Colitis Activity Index) and biochemical markers of inflammation (C-Reactive Protein, CRP). Fat free mass was estimated from skinfold thickness and Bioelectrical Impedance Analysis. Resting energy expenditure was measured by indirect calorimetry. A logarithmic correction and a linear regression model were used for analysis of REE corrected for body size. RESULTS: 55 children were studied; 37 (67%) with Crohn's disease and 18 (33%) with Ulcerative Colitis. Median PCDAI was 10 (range 0-60), 22 (59%) had PCDAI > or =10 (active disease). Median SCAI was 1.5 (range 0-12). Within disease groups there were strong correlations between REE/KgFFM(0.52) and disease activity; PCDAI (r -0.386, p 0.018) in Crohn's disease and SCAI (r -0.456, p 0.057) in Ulcerative Colitis. In the cohort as a whole there was no increase in REE/KgFFM(0.52) with increasing CRP (r 0.129, p 0.361). Using the regression model each mg/l increase in CRP was associated with a reduction in REE of nearly 1.5 kCal/day. CONCLUSIONS: We were unable to demonstrate a significant relationship between REE and disease activity in children with inflammatory bowel disease.