Preoperative risk factors for postoperative delirium.

The objective of this article was to estimate the incidence of delirium in a sample of patients undergoing elective surgery and to identify the preoperative factors most closely associated with developing this complication. Consecutive patients (n=500) underwent a full preoperative medical evaluation including assessment of cognitive and functional status. Daily evaluation on postoperative days 1 through 4 included medical record review and direct standardized patient interviews. Logistic regression was used to explore the associations between preoperative factors and postoperative delirium. Delirium was detected in 57 (11.4%) patients. Univariate factors associated with delirium included age> or =70 years (RR=3.1 [1.75,5.55]), preexisting cognitive impairment (RR=3.1 [1.73, 5.43]), greater preoperative functional limitations (RR=1.57 [1.27, 1.94]), and a history of prior delirium (RR 4.1 [1.98 to 8.27]. Adjusting for other factors, previous delirium (OR=4.08 [1.85, 9.0]), age> or =70 years (OR=3.2 [1.6, 6.0], and preexisting cognitive impairment (OR=2.16 [1.15, 4.0] remained predictive of delirium. Patients' perceptions that alcohol had affected their health (OR=6.53 [1.58 to 28.1]) and use of narcotic analgesics just prior to admission (OR=2.7 [1.37 to 5.3]) were also significantly associated with delirium postoperatively. Several easily obtained preoperative clinical factors can be used to identify patients at risk for postoperative delirium. This approach, when combined with specialized delirium teams using established guidelines, may be more effective in targeting patients at risk, thus reducing the number of episodes and days of delirium.

The cost of delirium in the surgical patient.

The authors identified the added cost attributable to postoperative delirium in patients undergoing elective surgery. The authors evaluated patients (n = 500) before their elective surgery, assessing cognitive functioning, medical conditions, medication usage, and other information regarding their health status. Using DSM-IV criteria, the authors assessed patients for delirium on Postoperative Days 1-4. Medical record review provided laboratory, radiological, and pharmaceutical information. The authors analyzed length of stay (LOS), comprehensive cost data collected through the hospital, and a group practice financial database to determine differences among those developing delirium. Of the 500 patients assessed, 57 (11.4%) developed delirium during the study. Delirium is an extremely costly disorder, both to the patient in terms of morbidity and mortality and to the medical facility. A prolonged LOS increases charges to third party payors and reduces return to physicians and hospitals when delirium develops. Careful presurgical screening and targeted postoperative interventions may help contain LOS and costs while affording greater physical, emotional, and cognitive health to patients hospitalized for elective surgery.