OUP accepted manuscript

Alterations in body composition are common in Inflammatory bowel disease (IBD) and have been associated with differences in patient outcomes. We have sought to consolidate knowledge on the impact and importance of body composition in IBD.We performed a systematic search of MEDLINE, EMBASE and conference proceedings by combining two key research themes: Inflammatory Bowel Disease and Body Composition.55 studies were included in this review. 31 studies focused on the impact of Inflammatory Bowel Disease on body composition with a total of 2,279 patients with mean age 38.4 years. Of these, 1,071 (47%) were male. 1470 (64.5%) patients had CD and 809 (35.5%) had UC. Notably, fat mass and fat-free mass were reduced, and higher rates of sarcopaenia were observed in those with active IBD compared with those in clinical remission and healthy controls. 24 additional studies focused on the impact of derangements in body composition on IBD outcomes. Alterations in body composition in IBD are associated with poorer prognoses including higher rates of surgical intervention, post-operative complications, and reduced muscle strength. In addition, higher rates of early treatment failure and primary non-response are seen in patients with myopaenia.Patients with IBD have alterations in body composition parameters in active disease and clinical remission. The impacts of body composition on disease outcome and therapy are broad and require further investigation. The augmentation of body composition parameters in the clinical setting has the potential to improve IBD outcomes in the future.