Postoperative Delirium is Associated with Negative Outcomes and Long-Term Mortality in Elderly Koreans: A Retrospective Observational Study

Background and objectives: Delirium is an acute state that causes confusion and occurs frequently after surgery in elderly patients. Delirium is also related to various clinical complications. With increasing numbers of surgeries performed on elderly Koreans, the number of cases of delirium and associated complications will likely rise. The purpose of the present study was to determine whether postoperative delirium in elderly Korean patients negatively influenced other clinical outcomes and their long-term mortality. Materials and Methods: The medical records of 1016 elderly patients (65 years or older) who underwent major abdominal surgery from January 2014 to December 2016 were retrospectively investigated. To determine long-term mortality, patients were followed for up to 12 months post-operation. Results: Delirium occurred in 194 patients (18.3%). Postoperative delirium was significantly associated with the length of hospital stay (B = 2.72), length of ICU stay (B = 18.78), adverse medical events (OR = 2.26, CI = 1.45-3.52), reoperation (OR = 5.50, CI = 1.66-18.22), ICU readmission (OR = 14.10, CI = 2.97-66.90), medical costs (B = 2473.85), discharge to somewhere other than the patient's home (OR = 6.01, CI = 3.35-10.76), hospital readmission (OR = 2.73, CI = 1.45-5.14), in-hospital mortality (OR = 3.34, CI = 1.21-9.19), three-month mortality (HR = 3.22, CI = 1.27-8.14), six-month mortality (HR = 2.85, CI = 1.28-6.36), and 12-month mortality (HR = 2.19, CI = 1.10-4.32). Conclusions: Postoperative delirium in elderly Korean patients was associated with negative clinical outcomes and mortality. For rapid recovery and increased survival rates in surgical patients, effective delirium-prevention care and active delirium treatments are necessary.