High risk of cognitive and functional decline after postoperative delirium. A three-year prospective study.

BACKGROUND/AIMS The aim of the study was to investigate the association of postoperative delirium with the outcomes of cognitive impairment, functional disability and death. METHODS Hip surgery patients aged 60 years or over (n = 200) underwent preoperative and daily postoperative assessment of their cognitive status during hospital stay. Outcome variables were determined at an average of 8 and 38 months after discharge from hospital. RESULTS Fourty-one patients developed postoperative delirium. Delirium was a strong independent predictor of cognitive impairment and the occurrence of severe dependency in activities of daily living. The associations were more marked for the long- than for the short-term outcome. Thirty-eight months after discharge from hospital, 53.8% of the surviving patients with postoperative delirium suffered from cognitive impairment, as compared to only 4.4% of the nondelirious participants. Logistic regression analysis adjusted for age, sex, medical comorbidity and preoperative cognitive performance revealed highly significant associations between delirium and cognitive impairment (OR = 41.2; 95% CI = 4.3-396.2), subjective memory decline (OR = 6.2; 95% CI = 1.5-25.8) and incident need for long-term care (OR = 5.6; 95% CI = 1.6-19.7). CONCLUSION The present study confirms a poor prognosis after delirium in elderly patients. The findings suggest that delirium does not simply persist for a certain time but also predicts a future cognitive decline with an increased risk of dementia.