Association Between Increased Neutrophil-to-lymphocyte Ratio and Postoperative Delirium in Elderly Patients with Total Hip Arthroplasty for Hip Fracture

Background: Delirium is a common complication in elderly patients with total hip arthroplasty (THA) for hip fracture. The mechanism of postoperative delirium (POD) is associated with the neuroinflammatory process. The aim of this study was to the incidence and perioperative risk factors of POD and investigate whether NLR could serve as a potential marker for POD in elderly patients with THA for hip fracture.

Methods: This was a multicenter prospective study, we included elderly patients with THA for hip fracture under general anesthesia. Receiver operating characteristic (ROC) curve was performed to identify the optimal cut point of NLR for POD. The relationship between NLR and POD was analyzed by multivariable analysis.

Results: Seven hundred eighty patients (mean age 73.33 ± 7.66) were eligible for inclusion in the study. 23.33% (182/780) of patients had POD. ROC curve analysis showed that the optimal cut point of NLR for POD was NLR ≥ 3.5. Compared with no POD, higher NLR, older age, diabetes, and higher neutrophil count were more likely in patients with POD(P < 0.05). Multivariate logistic regression analysis showed that NLR ≥ 3.50 [adjusted odds ratio(aOR), 3.93; confidence interval (CI), 2.47-6.25; P < 0.001)], older age (aOR, 1.04; 95%CI, 1.02-1.07; P = 0.001), diabetes (aOR, 1.58; 95% CI, 1.06-2.36; P = 0.025),higher neutrophil count (aOR, 1.25; 95%CI, 1.15-1.35; P < 0.001) were associated with increased risk of POD.

Conclusions: Older age, diabetes, higher neutrophil count, and NLR ≥ 3.5 were independent risk factors for POD, and NLR can be used as a potential marker for prediction of delirium in elderly patients with THA for hip fracture.