Introduction: Sarcopenia is an independent predictor of poor post-operative outcomes following major surgery. Inflammatory bowel disease (IBD) consists of Crohn's disease (CD) and ulcerative colitis (UC), which are chronic inflammatory conditions involving the gastrointestinal system. Evidence demonstrates that up to 60% of patients with IBD have sarcopenia. Despite advances in medical management, more than 15% of patients with UC and 80% with CD eventually require surgical intervention. The primary aim of the study was to assess the impact of sarcopenia on post-operative anastomotic leak rates. Methods: A retrospective cohort study of patients at Royal Perth Hospital who underwent major abdominal surgery for management of IBD between January 2010 and December 2020 was performed. Sarcopenia was assessed according to the skeletal muscle index at the level of the third lumbar vertebrae using the cut off 52.4 and 38.5 cm 2 /m 2 for men and women, respectively. Results: A total of 147 patients were included. The prevalence of sarcopenia within the study population was 36.1%. Patients with sarcopenia were significantly taller (P = 0.025) and were more likely to be on pre-operative steroid medications (P = 0.045). There was no difference in the remaining baseline characteristics between sarcopenic and non-sarcopenic patients. Patients with sarcopenia were more likely to develop a post-operative anastomotic leak (OR:11.303, 95% CI,, P = 0.017), grade IV complications (OR:6.79, 95% CI:1.1-43.6, P = 0.044) and require total parenteral nutrition (TPN) (OR:3.212, 95% CI:1.3-8.1, P = 0.013). Conclusions: Sarcopenia significantly increases the risk of major post-operative complications for patients with IBD undergoing colorectal surgery.

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