Preoperative neutrophil-to-lymphocyte ratio may contribute to the prediction of postoperative infectious complications in patients with acute appendicitis: a retrospective study

Background Several studies have assessed various clinical variables to identify risk factors for postoperative complications in patients with acute appendicitis. However, few studies have focused on the relationships between systemic inflammatory variables and postoperative complications in patients with acute appendicitis. We investigated the relationships between postoperative complications and systemic inflammatory variables, and assessed the clinical utility of these variables as predictors of postoperative complications in patients with acute appendicitis. Methods We retrospectively reviewed 181 patients who underwent immediate appendectomy for acute appendicitis. All postoperative complications were classified as infectious or noninfectious, and we evaluated the relationships between postoperative complications and clinical factors including the preoperative neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio. Results In total, 28 patients (15.5%) had postoperative Clavien-Dindo grade II–IV complications; 17 patients (9.4%) and 11 patients (6.1%) were categorized as the infectious and noninfectious complication groups, respectively. The cutoff value of the preoperative neutrophil-to-lymphocyte ratio for all complications was 11.3, and multivariate analysis revealed that the preoperative neutrophil-to-lymphocyte ratio was an independent predictor of any postoperative complication (odds ratio: 4.223, 95% confidence interval: 1.335–13.352; P = 0.014). The cutoff value of the preoperative neutrophil-to-lymphocyte ratio for infectious complications was 11.4, and multivariate analysis revealed that the preoperative neutrophil-to-lymphocyte ratio was an independent predictor of infectious complications (odds ratio: 4.235, 95% confidence interval: 1.137–15.776; P = 0.031). Conclusions In patients with acute appendicitis, the preoperative neutrophil-to-lymphocyte ratio may be a useful predictor of all postoperative complications, especially infectious complications.