Newly Published
Editorial Views  |   May 2019
The Devil Is in the Details: Comparison of Postoperative Delirium and Neurocognitive Dysfunction
Author Notes
  • From the Geriatric Behavioral Health Division, Department of Psychiatry and Behavioral Sciences (J.N.B.), and the Department of Anesthesiology (M.D.), Cardiothoracic Anesthesiology Division (J.P.M.), Duke University Medical Center, Durham, North Carolina.
  • Accepted for publication May 6, 2019.
    Accepted for publication May 6, 2019.×
  • Correspondence: Address correspondence to Dr. Browndyke: j.browndyke@duke.edu
Article Information
Editorial Views / Central and Peripheral Nervous Systems
Editorial Views   |   May 2019
The Devil Is in the Details: Comparison of Postoperative Delirium and Neurocognitive Dysfunction
Anesthesiology Newly Published on May 28, 2019. doi:10.1097/ALN.0000000000002823
Anesthesiology Newly Published on May 28, 2019. doi:10.1097/ALN.0000000000002823
Evaluating cognitive change within individuals (and in groups) has bedeviled neuropsychologists, biostatisticians, and clinicians for ages. In this issue of Anesthesiology, a study by Daiello et al.1  illustrates quite well some of the difficulties inherent in how we define and assess “clinically meaningful” postoperative cognitive outcomes and the practical impact those difficulties can have on determining the association between postoperative delirium and postoperative cognitive dysfunction—two conditions frequently associated with heightened risk for mortality within 1 yr after surgery, longer-term cognitive decline, and dementia.2–4 
In their examination of in-hospital postoperative delirium and postoperative cognitive dysfunction at 1, 2, and 6 months after noncardiac surgery in Successful Aging after Elective Surgery study participants,5  Daiello et al.1  report a weak association between in-hospital postoperative delirium and the risk of lingering postoperative cognitive dysfunction at 2 months of recovery (odds ratio = 1.30, P = 0.062) and a lack of association at 6 months of recovery (odds ratio = 1.07, P = 0.744). Their results suggest that the risk of significant postoperative cognitive dysfunction is really highest at 1 month in patients with in-hospital delirium (relative risk = 1.34, P = 0.010). Even then, only a small proportion of patients with both conditions at 1 month were found in their large surgery sample (75 of 548 patients; 14%) compared to the total patients with postoperative cognitive dysfunction at 1 month (256 of 548 patients; 47%). More patients developed postoperative cognitive dysfunction during the early stages of recovery without a history of in-hospital postoperative delirium. Although 12.5% of patients with postoperative cognitive dysfunction at 1 month were still evincing moderate to severe cognitive decline at 6 months of recovery, a history of postoperative delirirum was not predictive of persistent cognitive deficits. These findings demonstrate that postoperative delirium is poorly predictive of postoperative cognitive dysfunction after 1 month of recovery and beyond, suggesting that postoperative delirium and postoperative cognitive dysfunction are separate clinical conditions, rather than shared conditions reflecting two sides of the same coin.6