ObjectiveTo investigate the correlations of preoperative peripheral blood ghrelin levels and the albumin (ALB) / body mass index (BMI) ratio with the risk and severity of postoperative complications in gastric cancer. MethodsThe patients who underwent radical gastrectomy for gastric cancer at the 908th Hospital of the Joint Logistic Support Force of the People’s Liberation Army of China from September 2021 to June 2023 were enrolled. The incidence of postoperative complications during hospitalization was analyzed. Univariate and multivariate logistic regression analyses was used to analyze the effects of preoperative peripheral blood ghrelin levels and the ALB/BMI ratio on the risk of postoperative complications in gastric cancer. The predictive value of preoperative peripheral blood ghrelin levels, the ALB/BMI ratio, and their combination for postoperative complications in gastric cancer was evaluated using receiver operating characteristic (ROC) curves. Spearman correlation analysis was performed to analyze the correlation between preoperative peripheral blood ghrelin levels or the ALB/BMI ratio and the Clavien-Dindo grade of postoperative complications in gastric cancer. ResultsA total of 294 patients undergoing radical gastrectomy for gastric cancer were enrolled in this study, among whom 56 developed postoperative complications, with an overall complication rate of 19.05%. Univariate analysis revealed that age, preoperative comorbidities, combined organ resection, preoperative peripheral blood ghrelin levels, and ALB/BMI ratio were associated with postoperative complications following radical gastrectomy for gastric cancer (both P<0.05). Multivariate logistic regression analysis showed that, after adjusting for age, preoperative comorbidities, and combined organ resection, elevated ghrelin levels (OR=0.471, P<0.001) and increased ALB/BMI ratio (OR=0.454, P<0.001) remained independent protective factors against postoperative complications. The areas under the ROC curves (AUC) for preoperative peripheral blood ghrelin levels alone, the ALB/BMI ratio alone, and their combination in predicting postoperative complications in gastric cancer were 0.734, 0.749, and 0.864, respectively (all P<0.001). The DeLong test showed that the AUC of the combined prediction model was significantly higher than that of ghrelin levels alone and the ALB/BMI ratio alone (Z=2.985, P=0.003; Z=2.627, P=0.009). Spearman correlation analysis revealed that preoperative peripheral blood ghrelin levels and ALB/BMI ratio were negatively correlated with the severity of postoperative complications in gastric cancer (rs=–0.647, P<0.001; rs=–0.670, P<0.001). ConclusionsThe results indicate that preoperative peripheral blood ghrelin levels and ALB/BMI ratio of gastric cancer are related to the risk and severity of postoperative complications. The combined detection of the two has a high predictive value for postoperative complications of gastric cancer, which can provide a reference for preoperative prediction of the risk and severity of complications, but the research results still need to be further demonstrated by a prospective multi-center study.