Slow Gait Speed and Rapid Renal Function Decline Are Risk Factors for Postoperative Delirium after Urological Surgery

Abstract

Objectives: The aim of this study was to identify risk factors associated with postoperative delirium in patients undergoing urological surgery.

Methods: We prospectively evaluated pre- and postoperative risk factors for postoperative delirium in consecutive 215 patients who received urological surgery between August 2013 and November 2014. Preoperative factors included patient demographics, comorbidities, and frailty assessment. Frailty was measured by handgrip strength, fatigue scale of depression, fall risk assessment, and gait speed (the timed Get-up and Go test). Postoperative factors included types of anesthesia, surgical procedure, renal function and serum albumin decline, blood loss, surgery time, highest body temperature, and complications. Uni- and multivariate logistic regression analyses were performed to assess pre- and postoperative predictors for the development of postoperative delirium.

Results: Median age of this cohort was 67 years. Ten patients (4.7%) experienced postoperative delirium. These patients were significantly older, had weak handgrip strength, a higher fall risk assessment score, slow gait speed, and greater renal function decline compared with patients without delirium. Multivariate analysis revealed slow gait speed (>13.0 s) and rapid renal function decline (>30%) were independent risk factors for postoperative delirium.

Conclusions: Slow gait speed and rapid renal function decline after urological surgery are significant factors for postoperative delirium. These data will be helpful for perioperative patient management. This study was registered as a clinical trial: UMIN: R000018809.

Fig 1. Predictive value of the risk stratification.

A: Patients characteristics that were significantly different between the groups (*, P < 0.01). Error bar demonstrated 95% CI. B: ROC curve analysis to determine optimal cut-off values of age, gait speed in Get-up and Go test, and fall risk assessment scores. The AUC values were 0.89 in age, 0.87 in Get-up and Go test, and 0.79 in fall risk assessment score. The optimal cut-off values were age older than 75 years, slower than 13.0 s in the Get-up and Go test, and higher than 10 points in fall risk assessment score. C: Patients were categorized according to the number of independent predictors (>75 years old, Get-up and Go > 13.0 s, eGFR decline > 30%) for postoperative delirium (scores 0–3). The occurrence of postoperative delirium was 0% in score 0, 1.4% in score 1, 26% in score 2, and 67% in score 3 (P < 0.001). D: Predictive accuracy of selected three factors by the ROC curve showed that the AUC value was 0.952 (P < 0.001, 95% CI 0.902–1.00).