The Application Value of Preoperative Fat-free Mass Index within GLIM-defined Malnutrition Criteria for Postoperative Outcomes in Patients with Esophagogastric Cancer

• A low fat-free mass index (FFMI) is closely associated with postoperative complications. • An FFMI within Global Leadership Initiative on Malnutrition criteria is an important criterion for evaluating malnutrition. • The FFMI not only assesses malnutrition but also predicts clinical outcomes. The present study aimed to investigate the prognostic value of the preoperative fat-free mass index (FFMI) for postoperative outcomes in patients undergoing esophagogastric cancer surgery and to explore the role of the FFMI in the Global Leadership Initiative on Malnutrition (GLIM) criteria. This multicenter retrospective observational study took place in four teaching tertiary hospitals in China from September 2015 to June 2018. Malnutrition was diagnosed following the GLIM criteria. The evaluation of muscle mass (ie, the FFMI) as one of the constituents contained in the GLIM consensus was measured by bioelectrical impedance analysis. According to their FFMI per the GLIM criteria, patients with esophagogastric cancer were divided into a normal-FFMI group and a low-FFMI group. The observation indicators were postoperative complications, length of stay, wound healing time, postoperative antibiotic time, and nutritional status in the two groups. Of the 205 total patients with esophagogastric cancer, 76 (37.1%) were diagnosed with malnutrition. The normal-FFMI group had a significantly lower rate of postoperative complications (43 [33.3%] of 129 patients versus 37 [48.7%] of 76 patients; P = 0.038) and a shorter postoperative length of stay (12.6 ± 3.1 d versus 14.3 ± 3.2 d; P = 0.034), postoperative antibiotic time (5.3 ± 2.9 d versus 6.4 ± 2.1 d; P = 0.031), and wound healing time (10.9 ± 2.5 d versus 11.9 ± 3.1 d; P = 0.005) compared with the low-FFMI group. There were no significant differences between the groups in rates of other clinical outcomes. The body mass index (BMI) and FFMI were generally consistent in the diagnosis of malnutrition based on GLIM criteria (kappa, 0.464; P < 0.001). The linear correlation between BMI and FFMI (correlation coefficient, 0.659; P < 0.001) was moderate in patients with esophagogastric cancer who were at nutritional risk. The FFMI has an important role in the diagnosis of malnutrition using the GLIM criteria. In this study, a decreased preoperative FFMI was closely associated with postoperative complications in patients with esophagogastric cancer.