Abstract
PURPOSE: Inflammation may play a role in the mechanism of postoperative delirium (POD), a severe complication among older postoperative patients. The purpose of this study was to investigate the risk factors of POD in postoperative patients with hip fracture, especially the inflammation marker- neutrophil-lymphocyte ratio (NLR). METHODS: This retrospective investigation utilized data from the Seventh Medical Center of People's Liberation Army. 1,242 Eligible patients with hip fracture (829 females), median age 81 years, mean neutrophil-lymphocyte ratio (NLR) 5.28, were enrolled. Receiver operating characteristic (ROC) curve was performed to identify the optimal cut point of NLR for POD. The relationship between NLR and POD occurrence, NLR and POD duration were analyzed by multivariable analysis. RESULTS: ROC curve showed that the optimal cut point of NLR for POD was NLR ≥ 7.6. Multivariate logistic regression analysis showed that NLR ≥ 7.6 (odds ratio [OR] 2.75, [95% confidence interval [CI] 1.51 to 5.02], p = 0.001), stroke (OR 1.05, [95% CI 1.02 to 1.09], p = 0.005), complications, general anesthesia, long length of stay were risk factors of POD, with the largest effect for NLR ≥ 7.6. NLR ≥ 7.6 (β 0.59, [95% CI 0.209 to 0.886], p = 0.038), older age (β 0.054, [95% CI 0.009 to 0.099], p = 0.019), previous stroke (β 0.908, [95% CI 0.085 to 1.731], p = 0.031), and previous heart failure (β 1.679, [95% CI 0.448 to 2.910], p = 0.008) suggested long POD duration. CONCLUSIONS: This study demonstrates an association between NLR and postoperative delirium in geriatric hip fracture patients, and contribute new evidence to support NLR as a potential marker for prediction of POD and POD duration.