Postoperative delirium and 1-year functional decline, institutionalization and mortality

BACKGROUND: Postoperative delirium is a common and serious complication in older surgical patients and has been associated with increased morbidity, healthcare costs, long-term functional decline and mortality. OBJECTIVE: To determine whether postoperative delirium is associated with functional status, quality of life, institutionalisation and mortality at 1 year after surgery in a large multicentre surgical cohort. DESIGN: Prospective multicentre observational study. SETTING: Forty-three hospitals in Spain. Surgical patients were recruited in November 2023 and assessed for delirium 48 h after surgery, with follow-up at 1 year. PATIENTS, OTHER PARTICIPANTS: A total of 2442 adult surgical patients undergoing elective or urgent procedures requiring hospital admission. Postoperative delirium was assessed using the Confusion Assessment Method (CAM), CAM for the Intensive Care Unit (CAM-ICU) or the telephone-administered 4AT according to clinical setting. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Functional status and quality of life at 1 year assessed using the 12-item World Health Organization Disability Assessment Schedule (WHODAS 2.0). Secondary outcomes included institutionalisation and mortality. RESULTS: After excluding 81 deaths and 462 nonresponders, the 1-year telephone follow-up was completed for 1899 patients. Postoperative delirium within the first 48 h was independently associated with a 4.6-point higher WHODAS score at 1 year: adjusted mean difference = 4.60 [95% confidence interval (CI), 1.57 to 7.64, P = 0.003]. Delirium was also associated with increased institutionalisation and higher mortality: odds ratio (OR) 2.5 (95% CI, 1.07 to 5.84, P = 0.03), and (16.7 vs. 3.1%; P < 0.001), including 30-day, 60-day, and 365-day mortality (all P < 0.001), respectively. CONCLUSIONS: Postoperative delirium is independently associated with long-term functional decline, loss of independence, institutionalisation and increased 1-year mortality. These findings highlight delirium as a key perioperative complication and support prevention strategies and structured long-term follow-up after surgery. TRIAL REGISTRATION: ClinicalTrials.gov (identifier: NC-T06127901).