Delirium in older emergency department patients discharged home: Effect on survival

OBJECTIVES: To determine whether prevalent delirium is an independent predictor of mortality in older patients seen in emergency departments (EDs) and discharged home without admission. DESIGN: Prospective study with 18 months of follow-up. SETTING: EDs in two Montreal hospitals. PARTICIPANTS: From a cohort study of prognosis for delirium (107 delirious and 161 nondelirious subjects), 30 delirious and 77 nondelirious subjects aged 66 and older who were discharged home without admission were identified. MEASUREMENTS: Detailed interviews with patients and their proxies and review of medical charts were performed at enrollment. Trained lay interviewers determined delirium status using the Confusion Assessment Method. Subjects were followed up at 6-month intervals for a total of 18 months. Dates of death were obtained from the Ministere de la Sante et des Service Sociaux (Ministry of Health and Social Services). Survival analysis was performed using the Cox proportional hazards modeling adjusting for potential confounding variables. RESULTS: The analysis revealed a statistically significant association between delirium and mortality after adjustments for age, sex, functional level, cognitive status, comorbidity, and number of medications for the first 6 months of follow-up (hazard ratio = 7.24; 95% confidence interval = 1.62-32.35). The subjects whose delirium was not detected by the ED physician or nurse had the highest mortality over 6 months (30.8%). The mortality of delirious subjects detected in the ED was similar to that of the nondelirious subjects (11.8 vs 14.3%). CONCLUSION: The results of this study suggests that nondetection of delirium in the ED may be associated with increased mortality within 6 months after discharge. Further research is necessary to examine the effectiveness of improving detection on subsequent prognosis of older patients with delirium.