Postoperative delirium is an independent risk factor for posttraumatic stress disorder in the elderly patient: a prospective observational study.

BACKGROUND

Posttraumatic stress disorder (PTSD) may appear after hospitalisation for surgery with general anaesthesia in elderly patients. Prevalence and risk factors in this setting are unknown. Postoperative delirium could be a risk factor.

OBJECTIVE

The purpose of this study was to identify the prevalence of, and risk factors for, PTSD 3 months after surgery with general anaesthesia in elderly patients.

DESIGN

A prospective, clinical observational study.

SETTING

This study was carried out between March 2009 and May 2010 in a German university hospital in Berlin and was part of a larger study focusing on depth of anaesthesia.

INCLUSION CRITERIA: at least 60 years of age; noncardiac surgery with general anaesthesia.

EXCLUSION CRITERIA: impaired preoperative cognitive function [mini-mental state examination (MMSE) score <24]; expected surgery time less than 1 h; nonproficiency in the German language.

INTERVENTIONS: None.

MAIN OUTCOME MEASURES: Screening for PTSD 3 months after surgery using the screening instrument Post-Traumatic Stress Syndrome 14-Questions Inventory Score (PTSS-14). The following risk factors for PTSD 3 months after surgery were tested: age; American Society of Anesthesiologists physical status; sex; duration of anaesthesia; postoperative delirium; PTSS-14 score 7 days after surgery; postoperative vomiting and nausea; postoperative pain; and preoperative depression.

STATISTICS: Univariate statistical analysis was performed with Fisher's exact test and Spearman correlation. A backward logistic regression was performed.

RESULTS

A total of 559 out of 1277 patients were included. Sixty-six patients (12%) were identified with PTSD 3 months after surgery. Seventy-seven patients (14%) were identified with postoperative delirium. Independent associated factors in the backward logistic regression were postoperative delirium (risk factor) and preoperative depression (protective factor).

CONCLUSION

The prevalence of PTSD 3 months after surgery in elderly patients was high using the screening instrument PTSS-14. Postoperative delirium is a risk factor for PTSD 3 months after surgery.

TRIAL REGISTRATION: ISRCTN Register: 36437985. http://www.controlled-trials.com/ISRCTN36437985/