Predictive values of neutrophil to lymphocyte ratio, monocyte to lymphocyte ratio and platelet to lym-phocyte ratio for delirium after hip fracture surgery in the elderly / 中华创伤骨科杂志

ABSTRACT

Objective:To explore the predictive values of neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR) and platelet to lymphocyte ratio (PLR) for postoperative delirium in the elderly patients with hip fracture.Methods:The data of 1,278 elderly patients with hip fracture were analyzed retrospectively who had been admitted to Department of Orthopedics, The 7th Medical Center, General Hospital of Chinese People's Liberation Army from January 2012 to December 2018. There were 418 males and 860 females, with a median age of 81 (75, 90) years. There were 728 intertrochanteric fractures and 550 femoral neck fractures. The working characteristic curves (ROC) of NLR, MLR, and PLR used to predict postoperative delirium in the elderly patients with hip fracture were worked out to obtain the best cutoff points (sensitivity, specificity, and area under the curve) respectively. According to the best cutoff points, the NLR, MLR, and PLR were respectively divided into an increase group and a normal group. According to whether postoperative delirium occurred or not, the patients were divided into a delirium group and a delirium-free group. After univariable analysis was conducted to screen out the risk factors, binary logistic regression analysis was conducted of the factors with P<0.05 to determine the risk factors. Results:The median values of NLR, MLR and PLR in the 1,278 elderly patients with hip fracture at admission were 5.43 (3.87, 7.88), 0.40 (0.29, 0.54) and 158.40 (118.00, 222.50), respectively. Postoperative delirium occurred in 153 patients (12.0%). In the study of the predictive values of NLR, MLR, and PLR using ROC curves for postoperative delirium in the elderly patients with hip fracture, the best cutoff points (sensitivity, specificity, and area under the curve) for prediction were 7.613 (57.5%, 77.1%, 0.726), 0.512 (52.3%, 74.0%, 0.663), and 201.125 (68.6%, 73.3%, 0.751), respectively. The risk factors for postoperative delirium were increased NLR ( OR=2.046, 95% CI 1.322 to 3.166, P<0.001), increased MLR ( OR=1.568, 95% CI 1.039 to 2.367, P=0.032), and increased PLR ( OR=3.489, 95% CI 2.290 to 5.317, P<0.001). Conclusion:As NLR≥7.613, MLR≥0.512 and PLR≥201.125 may be risk factors for postoperative delirium in elderly patients with hip fracture, NLR, MLR and PLR may have a positive value in prediction of postoperative delirium.