Development and Validation of a Delirium Risk Prediction Model for Elderly Patients Undergoing Elective Orthopedic Surgery

Postoperative delirium following total joint arthroplasty: epidemiology, risk factors, and associated complications

INTRODUCTION

Postoperative delirium (POD) is a feared complication following major surgery in elderly patients. Further investigation of the risk factors and consequences of POD following total joint arthroplasty is warranted.

METHODS

Patients who underwent total knee arthroplasty (TKA) or total hip arthroplasty (THA) were identified using PearlDiver. Patients were filtered into 2 cohorts based on the presence or absence of POD within 7 days of surgery. Epidemiological analyses were performed to examine trends in POD following TKA and THA by age group and year. Comparative analyses were performed on patient demographics and baseline cognitive status. After matching by age, sex, and comorbidities, electrolyte disturbances and 90-day postoperative complications were analysed.

RESULTS

Among 2,518,918 (99.7%) no POD and 7240 (0.3%) POD patients who underwent total knee or hip arthroplasty, mean age was 65.58 years, 60.2% were female, and mean CCI was 1.50 for the whole cohort. POD patients frequently had baseline cognitive impairment (P < 0.001). Incidence of POD decreased from 0.54% in 2010 to 0.10% in 2022 (P < 0.001) and increased with age (P < 0.001). POD patients had higher 90-day costs (TKA = $19,572 vs. $10,397, P < 0.001; THA = $18,496 vs. $9,877 P < 0.001). After matching, POD TKA patients had higher rates of hypernatraemia (6.1% vs 4.5%, P = 0.001) and POD THA patients had higher rates of hyponatraemia (26.5% vs 23.1%, P = 0.008). POD patients had higher rates of 90-day postoperative medical and surgical complications (P < 0.05) than no POD patients.

CONCLUSIONS

Nearly 0.3% of patients who underwent either TKA or THA between 2010 and 2022 developed transient delirium. POD was most common in elderly patients with baseline cognitive impairment undergoing revision surgery. POD patients had higher rates of 90-day postoperative surgical and joint-related complications. While POD rates have decreased, continued initiative to prevent POD in total joint arthroplasty patients is imperative.

Risk factors and prediction model of delirium in elderly patients after hip arthroplasty

Objective

To analyze the risk factors of delirium in elderly patients after hip arthroplasty and to construct a prediction model.

Methods

Clinical data of 248 elderly patients who underwent hip arthroplasty in the Department of Traumatology and Orthopedics at Wuhan Fourth Hospital were retrospectively collected from November 2021 to February 2023. Logistic regression analysis was used to identify the risk factors of delirium after hip arthroplasty, and a nomogram prediction model was constructed using the RMS package of R4.1.2 software. The accuracy and stability of the model was evaluated based on the Hosmer-Lemeshow goodness-of-fit test and the receiver operating characteristic (ROC) curve.

Results

Age, nighttime sleep, anesthesia method, intraoperative blood loss, hypoxemia, and C-reactive protein (CRP) level were all risk factors of delirium after the hip arthroplasty (P<0.05). These factors were used to construct a nomogram prediction model that was internally validated using the Bootstrap method. The prediction model had the area under ROC curve (AUC) of 0.980 (95% CI: 0.964-0.996), indicating that it has certain predictive value for postoperative delirium. When the optimal cut off value was selected, the sensitivity and specificity were 92.7% and 92.3%, respectively, indicating that the prediction model is effective.

Conclusions

Age, short nighttime sleep, general anesthesia, high intraoperative blood loss, hypoxemia, and high CRP levels are independent risk factors for delirium after hip arthroplasty. The nomogram prediction model constructed based on these risk factors can effectively predict delirium in elderly patients after hip arthroplasty.