P521 Pre-operative enteral nutrition in adults with Crohn’s disease: effect on gut microbiota and disease outcomes

Abstract

Background: Exclusive enteral nutrition (EEN) in Crohn's disease (CD) can reduce disease activity and improve nutritional status before surgical resection. The mechanism of EEN action is unclear, but is proposed to involve profound modulation of the intestinal microbiota. The aim of this study was to evaluate the effect of preoperative EEN in adults with complicated CD and surgical indication, namely changes in gut microbiota induced by EEN. Methods: Prospective, non‐randomised study including adults CD patients with surgical indication. Patients with body mass index < 18.5 kg/m2, weight loss > 10% and/or serum albumin < 3 g/dl received EEN for at least 2 weeks. The remaining went straight to surgery. The impact of EEN on Harvey‐Bradshaw Index (HBI), C‐reactive protein (CRP), serum albumin, faecal calprotectin, and faecal microbiota was analysed on admission, after EEN but before surgery, and 6 months later. We used 16S rRNA gene sequencing to determine changes in the faecal microbiota. Immediate postoperative outcomes, clinical and endoscopic recurrence 6 months after surgery were compared between the two groups (pre‐operative EEN vs. direct surgery). Results: Fifteen patients were included, 9 male, with a mean age of 45.4 ± 19.1 years. Of these, 10 received EEN and 5 underwent direct surgery. The mean duration of pre‐operative EEN was 46 ± 24.5 days. During EEN there was a significant reduction in mean HBI (8.7 ± 1.9 vs. 4.1 ± 2.4, p = 0.001) and CRP (11.7 ± 10.3 vs. 0.8 ± 0.8 mg/dl, p = 0.008) and increase in albumin (3.1 ± 0.6 vs. 4.0 ± 0.6 g/dl p = 0.022). Immediately after EEN the overall microbial composition changed (PERMANOVA, 999 permutations, p = 0.046) and there were a significant reduction in α‐diversity (8.04 ± 2.32 vs. 5.21 ± 1.54, p = 0.023). EEN significantly decreased the relative abundance of 21 OTUs. At the family level, we found this was mainly due to the decrease of Enterobacteriaceae (6 OTUs). Six months after surgery α‐diversity increased, albeit not statistical significant; 9 OTUs increased: 4 OTUs belonged to Lachnospiraceae family and 3 to Enterobacteriaceae family. The incidence of postoperative complications and length of hospital stay were similar in both groups, as well as clinical and endoscopic recurrence rates 6 months after surgery. Conclusions: Pre‐operative EEN improved disease activity and nutritional status in patients with CD before surgery. During EEN overall microbial composition changed and α‐diversity decreased. Despite being malnourished, patients submitted to EEN did not have increased postoperative morbidity when compared with wellnourished ones. In this study, EEN did not influence postoperative clinical and endoscopic recurrence.