Supplementary Material for: Clinical significance of the preoperative inflammatory burden index in esophageal cancer

Introduction: The inflammatory burden index (IBI) serves as a prognostic marker for several cancers. Here, we evaluated the predictive value of preoperative IBI associated with the surgical and oncological outcomes of patients with esophageal cancer (EC). Methods: The IBI was formulated as C-reaction protein x neutrophil/lymphocyte. We retrospectively analyzed preoperative IBI of 147 EC patients receiving esophagectomy between 2008 and 2018. Cox proportional hazards models and multivariable logistic regression were employed to identify independent risk factors of surgical site infection and prognosis. Results: Increased preoperative IBI significantly correlated with higher tumor stage. Patients with high IBI experienced shorter overall survival (P = 0.0002) and disease-free survival (P = 0.002) compared with those with low IBI. In the adjusted Cox-proportional hazards regression models, increased IBI served as an independent prognostic factor for overall survival (hazard ratio, 3.56; 95% confidence interval, 1.79–7.34; P = 0.0003) and disease-free survival (hazard ratio, 3.03; 95% confidence interval, 1.60–5.92; P = 0.007). Multivariable analysis identified preoperative high IBI served as an independent risk factor for overall surgical site infection (odds ratio, 2.53; 95% confidence interval, 1.00–6.38; P = 0.049). Conclusion: Preoperative IBI may serve as a useful predictor of prognosis and surgical site infection of patients with EC after esophagectomy.