Postoperative excessive gain in visceral adipose tissue as well as body mass index are associated with adverse outcomes of an ileal pouch

Background: There are no published studies on the impact of visceral adipose tissue (VAT) change on outcomes of restorative proctocolectomy and ileal pouch-anal anastomosis (IPAA). The aim of this historic cohort study was to evaluate the impact of excessive VAT gain on the outcomes of inflammatory bowel disease (IBD) patients with IPAA.

Methods: We evaluated all eligible patients with at least two sequential CT scans after pouch construction from our prospectively maintained Pouchitis Registry between 2002 and 2014. The visceral fat area (VFA) was measured on CT images. The study group comprised patients with a significant VAT gain (> 15%), and the control group was those without. The adverse outcomes of the pouch were defined as the new development of chronic pouch inflammation (chronic pouchitis, chronic cuffitis or Crohn's disease of the pouch), anastomotic sinus and the combination of above (the composite adverse outcome) or pouch failure, after the inception CT.

Results: Of 1564 patients in the Registry, 59 (3.8%) with at least 2 CT scans after pouch surgery were included. Twenty-nine patients (49.2%) were in the study group, and 30 (50.8%) were in the control group. The median duration from the inception to the latest CT was 552 (range: 31-2598) days for the entire cohort. We compared the frequency of new chronic pouch inflammation (13.8% vs 3.3%, P = 0.195), new pouch sinus (10.3% vs 0%, P = 0.112), composite adverse pouch outcome (24.1% vs 3.3%, P = 0.026) or pouch failure (10.3% vs 6.7%, P = 0.671) between the two groups. Kaplan-Meier plot for time-to-pouch failure between the pouch patients with or without excessive body mass index (BMI) gain (> 10%) showed statistical difference (P = 0.011). Limited stepwise multivariate analysis showed that excessive VAT gain (odds ratio = 12.608, 95% confidence interval: 1.190-133.538, P = 0.035) was an independent risk factor for the adverse pouch comes.

Conclusions: In this cohort of ileal pouch patients, excessive VAT gain as well as gain in BMI after pouch construction was found to be associated with poor long-term outcomes.