Abstract:

Objective

To investigate the the predictive value of the monocyte-to-lymphocyte ratio （MLR） for postoperative pulmonary infection （PPI） in elderly patients with hip fractures.

Methods

A retrospective analysis was conducted on clinical data from 265 elderly hip fracture patients admitted to a tertiary hospital in Hangzhou between January 2018 and December 2024. Patients were divided into a pulmonary infection group and a non-infection group based on the occurrence of PPI. Univariate analysis was used to identify risk factors for PPI. Receiver operating characteristic （ROC） curves were plotted to evaluate the predictive value of MLR postoperatively for PPI in elderly patients with hip fractures. The further analysis of independent risk factors was conducted using a multiple logistic regression model.

Results

The incidence of PPI in elderly hip fracture patients was 5.7% （15/265）. Univariate analysis revealed that ICU admission and elevated MLR at 24 hours postoperatively were associated with PPI（P ＜ 0.05）. Multivariate analysis demonstrated that MLR≥0.7 postoperatively was an independent risk factor for PPI （OR=4.161， 95%CI： 1.038-16.676， P ＜ 0.05）. The area under the ROC curve （AUC） for MLR in predicting PPI was 0.691 （95%CI： 0.561-0.820， P ＜ 0.05）， with an optimal cutoff value of 0.7.

Conclusion

An early postoperative MLR value of ≥0.7 in elderly hip fracture patients is associated with PPI. This biomarker may aid in early clinical identification of high-risk patients.

Key words: Aged, Hip fracture, Postoperative pulmonary infection, Monocyte, Lymphocyte