A Nomogram to Predict Delirium after Hip Replacement in Elderly Patients with Femoral Neck Fractures

OBJECTIVE: Postoperative delirium (POD) is a common complication, and clinical practitioners have taken measures to improve the quality of life after hip replacement surgery. We aim to establish a nomogram to predict POD in elderly patients with femoral neck fractures (FNFs) after hip replacement. METHODS: A total of 384 elderly patients (267 females) with an average age of 75.8 years who underwent hip replacement from June 2010 to May 2020 were retrospectively reviewed. Patients were divided into delirium and non‐delirium groups according to the confusion assessment method. The risk factors for POD were analyzed by multivariate logistic regression, and the nomogram was established based on the results. RESULTS: The incidence of POD was 33.33% (128/384). Univariate analysis showed that advanced age, diabetes, lacunar cerebral infarction, surgery type, intraoperative blood loss, electrolyte imbalance, and anemia were risk factors for POD (p < 0.05). Multivariate logistic regression revealed that the independent risk factors for POD were age (OR = 1.332, 95% CI [1.224, 1.449], p < 0.01), surgery type (OR = 0.351, 95% CI [0.137, 0.900], p = 0.029), electrolyte imbalance (OR = 4.407, 95% CI [1.947, 9.977], p< 0.01), anemia (OR = 10.819, 95% CI [4.573, 25.598], p < 0.01). The prediction equation was established; logistic (p) = −25.469 + 0.277*X1(age[value = years of age]) + 1.293*X2(surgery[value = 0 for “total hip replacement” or value = 1 for “hemiarthroplasty”]) + 1.510*X3(electrolyte imbalance[value = 0 for “no” or value = 1 for “yes”]) + 2.157*X4(anemia[value = 1 for “hemoglobin with < 120g/L in male and < 110g/L in female patients” ]) or 2.975*X5(anemia[value = 1 for “hemoglobin with <90g/L"]). The area under the curve was 0.957 (95% CI [0.938, 0.976], p < 0.01). CONCLUSION: The incidence of POD in elderly patients with FNF after hip replacement is high. The nomogram incorporating age, surgery type, electrolyte imbalance, and anemia could provide an individualized prediction for POD among FNF patients after hip replacement, which may help the physician determine appropriate perioperative management.