Unrecognized Incident Delirium in Older Emergency Department Patients

Background It is documented that health professionals from various settings fail to detect > 50% of delirium cases. Objective This study aimed to describe the proportion of unrecognized incident delirium in five emergency departments (EDs). Secondary objectives were to compare the two groups (recognized/unrecognized) and assess the impact of unrecognized delirium at 60 days regarding 1) unplanned consultations and 2) functional and cognitive decline. Method This is a sub-analysis of a multicenter prospective cohort study. Independent patients aged ≥ 65 years who tested negative for delirium on the initial interview with an ED stay ≥ 8 h were enrolled. Patients were assessed twice daily using the Confusion Assessment Method (CAM) and the Delirium Index up to 24 h into hospital admission. Medical records were reviewed to assess whether delirium was recognized or not. Results The main study reported a positive CAM in 68 patients. Three patients’ medical files were incomplete, leaving a sample of 65 patients. Delirium was recognized in 15.4% of our participants. These patients were older (p = 0.03) and female (p = 0.01) but were otherwise similar to those with unrecognized delirium. Delirium Index scores were higher in patients with recognized delirium (p = 0.01) and they experienced a more important functional decline at 60 days (p = 0.02). No association was found between delirium recognition and health care services utilization or decline in cognitive function. Conclusions This study confirms reports of high rates of missed or unrecognized delirium (84.6%) in ED patients compared to routine structured screening using the CAM performed by a research assistant. Patients with recognized delirium were older women with a greater severity of symptoms and experienced a more significant functional decline at 60 days.