Analysis of Delirium Risk Assessment Tools for Prediction of Postoperative Delirium Following Lumbar Spinal Fusion

Study Design. Retrospective cohort study. Objective. Evaluate the utility of Delirium Risk Assessment Score (DRAS), Delirium Risk Assessment Tool (DRAT), and Delirium Elderly At-Risk (DEAR) in patients undergoing posterior lumbar interbody fusions. Background. Surgical interventions can place patients at risk for postoperative delirium (POD), an acute and often severe cognitive impairment associated with poor outcomes. However, common risk assessment tools have not been validated in patients undergoing spine surgery. Materials and Methods. Adults who underwent posterior lumbar fusion were queried using PearlDiver. Baseline demographics, comorbidities, and delirium occurrence within seven days of surgery were extracted. Delirium risk scores were calculated using DRAS (15 points total; threshold five points), DRAT (eight points total; threshold three points), and DEAR (five points total; threshold two points) scales. Receiver operating characteristic (ROC) curves were generated, and optimal risk scores maximizing Youden index were established for each measure. Results. Among 37,119 patients, 70 patients (0.2%) developed POD. The mean age was 60.1 y, 56.6% were female, and mean Charlson comorbidity index (CCI) was 2.1. POD patients had lower mean age and percent female sex, but higher mean CCI and percent medical comorbidities (all P <0.05). ROC curve analyses revealed that a DRAS score of five (sensitivity=62.9%, specificity=63.9%), DRAT score of three (sensitivity=31.4%, specificity=81.0%), and DEAR score of two (sensitivity=40.0%, specificity=82.9%) maximized the Youden index value. Patients above these thresholds were 6.0, 2.0, and 3.2 times more likely to develop POD after posterior lumbar fusion, respectively. Conclusion. Delirium risk assessments tools were found to be useful in stratifying patients at high risk of POD following posterior lumbar fusion. Specifically, patients above the predefined thresholds were two to six times more likely to develop delirium postoperatively. Careful stratification of patients’ risk of delirium using highly sensitive and specific tools like DRAS may guide preoperative surgical planning and postoperative management plans. Level of Evidence. Level IV.