Executive Function and Depression as Independent Risk Factors for Postoperative Delirium

Abstract

Background Postoperative delirium has been associated with greater complications, medical cost, and increased mortality during hospitalization. Recent evidence suggests that preoperative executive dysfunction and depression may predict postoperative delirium; however, the combined effect of these risk factors remains unknown. We therefore examined the association between preoperative executive function, depressive symptoms, and established clinical predictors of postoperative delirium among 998 consecutive patients undergoing major non-cardiac surgery. Methods Nine hundred ninety eight patients were screened for postoperative delirium (n = 998) using the Confusion Assessment Method as well as through retrospective chart review. Patients underwent cognitive, psychosocial, and medical assessments preoperatively. Executive function was assessed using the Concept Shifting Task, Letter-Digit Coding, and a modified Stroop Color Word Interference Test. Depression was assessed by the Beck Depression Inventory. Results Preoperative executive dysfunction (P = .007) and greater levels of depressive symptoms (P = .049) were associated with a greater incidence of postoperative delirium, independent of other risk factors. Secondary analyses of cognitive performance demonstrated that the Stroop Color Word Interference Test, the executive task with the greatest complexity in this battery, was more strongly associated with postoperative delirium than simpler tests of executive function. Furthermore, patients exhibiting both executive dysfunction and clinically significant levels of depression were at greatest risk for developing delirium postoperatively. Conclusions Preoperative executive dysfunction and depressive symptoms were predictive of postoperative delirium among non-cardiac surgical patients. Executive tasks with greater complexity are more strongly associated with postoperative delirium relative to tests of basic sequencing.

Incidence and predictors of delirium after cardiac surgery: Results from The IPDACS Study

“…Depression and depressive symptoms were previously associated with postoperative delirium in patients who underwent major non-cardiac operations [25,26]. However, the association between depression and delirium after cardiac surgery has remained unknown [3,21,23].…”

Managing acute behavioural disturbance in a neurology ward

“…In terms of identification of ‘at risk’ patients, evaluation of executive function and intercurrent depressive illness39 40 appear more predictive than memory tests, particularly when cognitive impairment is less overt.…”

Anaesthesia for the patient with dementia undergoing outpatient surgery

“…Postoperative cognitive dysfunction (POCD) is another much more subtle cognitive disorder that is often unnoticed when patients are discharged from the hospital. Symptoms vary amongst patients but usually involve a decline in memory, concentration, and information processing [40,[41][42][43]. The risk of experiencing POCD is lower following minor surgery, but studies on POCD have excluded demented patients so the exact incidence for these patients is still unknown.…”

“…The risk of experiencing POCD is lower following minor surgery, but studies on POCD have excluded demented patients so the exact incidence for these patients is still unknown. Delirium and POCD differ significantly in clinical presentation and duration (Table 1), but both are associated with higher mortality and morbidity rates [41,42,44 ].…”