Background: In metabolic-bariatric fast-track surgery, patients are scheduled for discharge on postoperative day 1. The neutrophil-to-lymphocyte ratio (NLR) could be an inexpensive and rapid way to... Show moreBackground: In metabolic-bariatric fast-track surgery, patients are scheduled for discharge on postoperative day 1. The neutrophil-to-lymphocyte ratio (NLR) could be an inexpensive and rapid way to identify patients at risk of early complications. This study aimed to determine the predictive value of the NLR on early complications.Methods: Prospective data were collected of all patients undergoing primary metabolic surgery in a single center, between April 2018 and April 2019. The association between NLR, leukocyte count, hemoglobin, and C-reactive protein (CRP) was compared with early complications.Results: In total, 829 patients underwent primary metabolic surgery: 336 (40.5%) Roux-en-Y gastric bypass, 410 (49.5%) sleeve gastrectomy, and 83 (10.0%) one anastomosis gastric bypass. Major complications occurred in 34 (4.1%) patients, who had significantly higher levels of postoperative NLR (p < 0.001), delta-NLR (p < 0.001), leukocyte count (p < 0.001), and CRP (p = 0.008). The ideal cutoff points to predict complications after metabolic surgery were 6.73 for postoperative NLR (sensitivity 74% and specificity 70%) and 4.68 for delta-NLR (sensitivity 77% and specificity 75%).Conclusion: Postoperative NLR and delta-NLR were independently associated with early major complications after metabolic surgery. These markers may be useful to help identify patients who are at risk for complications, and can aid in the decision making for safe postoperative discharge on day 1 or early intervention. Show less