Abstract: Abstract: Objective　To investigate the predictive value of red cell distribution width (RDW) of postoperative lung infection in elderly patients with hip fracture. Methods　Clinical data including age, gender, fracture information, intraoperative information and hemoglobin, albumin and RDW of a total of 1 341 elderly patients with hip fracture were collected. The receiver operating characteristic (ROC) curve was used to determine the optimal cut-off value of RDW. Patients were divided into the low RDW group and the high RDW group. The relationship between RDW and postoperative pulmonary infection and the predictive value of RDW were analyzed. Results　The incidence of postoperative lung infections was 5.89% in elderly patients with hip fracture. The RDW level of patients with postoperative lung infections was significantly higher than that of patients without postoperative lung infections. ROC curve showed that RDW predicted the risk of postoperative pulmonary infection with 0.638 area under the curve (95%CI: 0.576~0.700，P＜0.01), the corresponding optimal diagnostic threshold was 13.1%, the sensitivity was 69.6%, and the specificity was 55.9%. Patients were divided into the low RDW group (RDW≤13.1%, n=758) and the high RDW group (RDW＞13.1%, n=583). Compared with the low RDW group, there was a higher incidence of postoperative pulmonary infection in the high RDW group (3.4% vs. 9.1%, P＜0.05). Multivariate Logistic regression analysis demonstrated that RDW＞13.1% was an independent risk factor for postoperative lung infection in elderly patients with hip fracture (OR=2.191，95%CI：1.311-3.661，P＜0.05). Conclusion　High RDW level is an independent risk factor for postoperative lung infection in elderly hip fracture patients. The RDW value has predictive value for onset of postoperative pulmonary infection in elderly patients with hip fracture.

Key words: hip fractures, postoperative complications, postoperative lung infections, red cell distribution width, aged