Prevalence, management and outcomes of unrecognized delirium in a National Sample of 1,493 older emergency department patients: How many were sent home and what happened to them?

Background: Retrospective studies estimate Emergency Department (ED) delirium recognition at <20%; few prospective studies have assessed delirium recognition and outcomes for patients with unrecognized delirium. Objectives: To prospectively measure delirium recognition by ED nurses and physicians, document their confidence in diagnosis and disposition, actual dispositions, and patient outcomes. Methods: Prospective observational study of people ≥65 years. We assessed delirium using the Confusion Assessment Method, then asked ED staff if the patient had delirium, confidence in their assessment, if the patient could be discharged, and contacted patients 1 week postdischarge. We report proportions and 95% confidence intervals (Cls). Results: We enrolled 1,493 participants; mean age was 77.9 years; 49.2% were female, 79 (5.3%, 95% CI 4.2-6.5%) had delirium. ED nurses missed delirium in 43/78 cases (55.1%, 95% CI 43.4-66.4%). Nurses considered 12/43 (27.9%) patients with unrecognized delirium safe to discharge. Median confidence in their delirium diagnosis for patients with unrecognized delirium was 7.0/10. Physicians missed delirium in 10/20 (50.0%, 95% CI 27.2-72.8) cases and considered 2/10 (20.0%) safe to discharge. Median confidence in their delirium diagnosis for patients with unrecognized delirium was 8.0/10. Fifteen patients with unrecognized delirium were sent home: 6.7% died at 1 week follow-up vs. none in those with recognized delirium and 1.1% in the rest of the cohort. Conclusion: Delirium recognition by nurses and physicians was sub-optimal at ~50% and may be associated with increased mortality. Research should explore root causes of unrecognized delirium, and novel strategies to systematically improve delirium recognition and patient outcomes.