Short‐Term Clinical Outcomes and Complication Timing in Patients With Postoperative Delirium After Major Emergency Abdominal Surgery: A Prospective Cohort Study

BACKGROUND: Postoperative delirium is linked to increased morbidity, mortality, and prolonged hospitalization; however, its short-term consequences after major emergency abdominal surgery remain insufficiently studied. METHODS: This prospective cohort study included 752 patients undergoing major emergency abdominal surgery at Copenhagen University Hospital, Herlev, from 2021 to 2022. Delirium was identified via systematic screening and record review. The primary outcome was Comprehensive Complication Index (CCI). Secondary outcomes included Intensive Care Unit (ICU) admission, length of stay, discharge destination, and 30-day mortality. Multivariable logistic regression identified risk factors. The timing of complications relative to delirium onset was examined. RESULTS: Delirium occurred in 175 (23%) patients and was associated with higher CCI (median 44 vs. 9) and longer stay (13 vs. 6 days), more ICU admissions (36% vs. 13%), and higher 30-day mortality (22% vs. 8%) (all p < 0.001). Delirium was associated with more frequent discharge to long-term care. Risk factors for delirium included higher age, higher degree of frailty, intraperitoneal contamination, and damage control surgery. The incidence rate of complications was significantly lower than in the pre-delirium period (IRR = 0.49, 95% CI: 0.39-0.60, p < 0.001), with the highest rate observed on the day of delirium onset (0.72 events per patient-day at risk). CONCLUSIONS: Delirium was strongly associated with worse short-term outcomes after emergency abdominal surgery. Delirium onset coincided with the highest complication rate, underscoring the systemic physiological stress associated with delirium. These findings support the importance of early detection of delirium and possible prevention strategies.