Objective To investigate the correlation between preoperative N-terminal pro-B-type natriuretic peptidogen(NT-proBNP)levels and early postoperative outcomes in elderly and critically ill pa-tients with hip fractures.Methods A total of 593 elderly and critically ill patients with hip fractures from January 2018 to April 2021 were selected,including 189 males and 404 females,aged≥65 years,BMI 12.0-35.5 kg/m2,ASA physical status Ⅱ-Ⅳ.General preoperative information,intraoperative and post-operative discharge outcomes of patients were retrospectively obtained by the electrical clinical medical record system or telephone follow-up.The receiver operator characteristic(ROC)curve of preoperative plas-ma NT-proBNP and postoperative 30-day death was plotted,and the corresponding optimal cut-off value was 1 765.0 pg/ml.According to NT-proBNP values,the patients were divided into two groups:low-ratio group(NT-proBNP≤1 765.0 pg/ml,group L,n = 463)and high-ratio group(NT-proBNP＞1 765.0 pg/ml,group H,n = 130).The correlation between different plasma concentrations of NT-proBNP before surgery and ICU length of stay,total length of stay,postoperative complications,and 30-day mortality rate were an-alyzed using univariate and multivariate logistic regression analysis.Results Compared with group L,age,preoperative comorbidities with coronary heart disease,arrhythmia,chronic heart failure,lung disease,and chronic kidney disease,as well as mortality within 30 days after surgery were significantly increased in group H(P＜0.05).The multivariate logistic regression analysis showed that high preoperative plasma NT-proBNP concentration was positive correlation with postoperative ICU length of stay(OR = 1.215,95%CI 1.073-1.375,P = 0.020)and 30-day mortality rate(OR = 32.696,95%CI 7.158-149.338,P＜0.001).Conclusion High preoperative plasma NT-proBNP concentration is positive correlation with postoperative ICU hospitalization timeand 30-day mortality.