The relationship between the psoas muscle mass index and postoperative complications in Crohn's Disease : A retrospective cohort study

Abstract Background: Sarcopenia is generally defined based on the age-related muscle mass and weakness. However, it has been reported that patients with Crohn’s disease, who develop severe inflammation of the gastrointestinal tract, are more likely to develop sarcopenia. We retrospectively investigated the effect of the iliopsoas muscle area, which is an indicator of sarcopenia, on postoperative complications in patients with Crohn's disease. Methods: We retrospectively analyzed 74 patients with Crohn's disease who underwent surgery in our department between January 2016 and November 2019. The psoas muscle index (PMI) was calculated as the average of the left and right iliopsoas muscles (L3, cm²) / height². The patients were divided into the low PMI (male <2.33 cm²/m², female <1.85 cm²/m²) and normal PMI groups. Preoperative and intraoperative factors and the postoperative outcomes were compared between the two groups. Results: The median age of the 74 patients was 37.6 (17-70) years. Complications were noted in 32 patients (43.2%), including 9 (12.2%) with anastomotic leakage. There were 21 (28.4%) patients with a low PMI. The incidence of all postoperative complications, complications, grade≥3 complications, and anastomotic leakage were significantly higher in the low-PMI group than in the normal-PMI group. According to a multivariate analysis, low PMI (p=0.04) was the only independent predictor of postoperative complications. Conclusion: A low PMI is associated with postoperative complications, especially anastomotic leakage, in patients with Crohn's disease. In the low-PMI group, the risk of anastomotic leakage was high, and the creation of a colostomy without anastomosis was considered as an option.