Abstract: Objective To investigate the clinical predictive value of neutrophil extracellular trap (NETs) in diagnosis of postoperative pneumonia in elderly patients with hip fracture.Methods A total of 168 elderly patients with hip fracture hospitalized in our hospital from February 2021 to February 2023 were selected and divided into pneumonia group (52 cases) and non-pneumonia group (116 cases) according to whether they developed pneumonia after surgery.The clinical data and postoperative neutrophils (NEU),lymphocytes (LYM),platelets (PLT),NLR (ratio of NEU to LYM),N/LPR (ratio of NEU to LYM to PLT) and plasma myeloperoxidase DNA (MPO-DNA) representing the level of NETs were compared between the two groups.Multivariate Logistic regression was used to analyze the risk factors for postoperative pneumonia,and the predictive value of statistically significant variables for postoperative pneumonia was evaluated.Results The contents of age,NLR,N/LPR and MPO-DNA in pneumonia group were significantly higher than those in non-pneumonia group (P<0.05).Multivariate Logistic regression analysis showed that the increase of N/LPR and MPO-DNA indexes was an independent risk factor for postoperative pneumonia in elderly patients with hip fracture.ROC curve results showed that N/LPR and MPO-DNA indexes were of high predictive value in elderly patients with postoperative hip fracture pneumonia,and the curve area (AUC) of MPO-DNA indexes was higher than that of N/LPR indexes.Conclusions The level of NETs in elderly patients with postoperative pneumonia after hip fracture is significantly increased,and the increase of NETs is an independent risk factor for postoperative pneumonia in patients,and the content of NETs is of high diagnostic value for postoperative pneumonia.

Key words: neutrophil extracellular trap, hip fracture, old age, postoperative pneumonia, predictive value