Long-term outcomes of delirium in critically ill surgical patients: A multicenter prospective cohort study

Objective: To identify the mortality rates and dependency rate (functional outcomes) of delirious patients at 12-months after surgical intensive care unit (SICU) admission and to determine the independent risk factors of 12-months mortality and dependency rate in a cohort of SICU patients. Methods: A prospective, multi-center study was conducted in 3 university-based hospitals. Critically-ill surgical patients who were admitted to SICU and followed-up at 12-months after ICU admission were enrolled. Results: A total of 630 eligible patients were recruited. 170 patients (27%) had postoperative delirium (POD). The overall 12-months mortality rate in this cohort was 25.2%. Delirium group showed significantly higher mortality rates than non-delirium group at 12-months after ICU admission (44.1% vs 18.3%, P < 0.001). Independent risk factors of 12-months mortality were age, diabetes mellitus, preoperative dementia, high Sequential Organ Failure Assessment (SOFA) score and POD. POD was associated with 12-months mortality (adjusted hazard ratio, 1.49; 95% confidence interval 1.04–2.15; P = 0.032). The dependency rate defined as the Basic Activities Daily Living (B-ADL) ≤70 was 52%. Independent risk factors of B-ADL were age ≥ 75 years, cardiac disease, preoperative dementia, intraoperative hypotension, on mechanical ventilator and POD. POD was associated with dependency rate at 12-months. (adjusted risk ratio, 1.26; 95%CI 1.04–1.53; P = 0.018). Conclusions: Postoperative delirium was an independent risk factor of death and was also associated with dependent state at 12 months after a surgical intensive care unit admission in critically ill surgical patients.