Association between postoperative delirium and adverse outcomes in older surgical patients: A systematic review and meta-analysis

Study objective: To assess the incidence of postoperative delirium and its outcomes in older non-cardiac surgical patients. Design: A systematic review and meta-analysis with multiple databases searched from inception to February 22, 2022. Setting: Postoperative assessments. Patients: Non-cardiac and non-neurological surgical patients aged & GE;60 years with and without postoperative delirium. Included studies must report & GE;1 postoperative outcome. Studies with a small sample size (N < 100 subjects) were excluded. Measurements: Outcomes comprised the pooled incidence of postoperative delirium and its postoperative outcomes, including mortality, complications, unplanned intensive care unit admissions, length of stay, and nonhome discharge. For dichotomous and continuous outcomes, OR and difference in means were computed, respectively, with a 95% CI. Main results: Fifty-four studies (20,988 patients, 31 elective studies, 23 emergency studies) were included. The pooled incidence of postoperative delirium was 19% (95% CI: 16%, 23%) after elective surgery and 32% (95% CI: 25%, 39%) after emergency surgery. In elective surgery, postoperative delirium was associated with increased mortality at 1-month (OR: 6.60; 95% CI: 1.58, 27.66), 6-month (OR: 5.69; 95% CI: 2.33, 13.88), and 1year (OR: 2.87; 95% CI: 1.63, 5.06). The odds of postoperative complications, unplanned intensive care unit admissions, prolonged length of hospital stay, and non-home discharge were also higher in delirium cases. In emergency surgery, patients with postoperative delirium had greater odds of mortality at 1-month (OR: 3.56; 95% CI: 1.77, 7.15), 6-month (OR: 2.60; 95% CI: 1.88, 3.61), and 1-year (OR: 2.30; 95% CI: 1.77, 3.00). Conclusions: Postoperative delirium was associated with higher odds of mortality, postoperative complications, unplanned intensive care unit admissions, length of hospital stay, and non-home discharge. Prevention and perioperative management of delirium may optimize surgical outcomes.