Abstract
BACKGROUND: The natural course and clinical significance of delirium in the emergency department (ED) is unclear. OBJECTIVES: We sought to (1) describe the extent to which delirium in the ED persists into hospitalization (ED delirium duration) and (2) determine how ED delirium duration is associated with 6-month functional status and cognition. DESIGN: Prospective cohort study. SETTING: Tertiary care, academic medical center. PARTICIPANTS: ED patients ≥65 years old who were admitted to the hospital. MEASUREMENTS: The modified Brief Confusion Assessment Method was used to ascertain delirium in the ED and hospital. Premorbid and 6-month function were determined using the Older American Resources and Services Activities of Daily Living (OARS ADL) questionnaire which ranged from 0 (completely dependent) to 28 (completely dependent). Premorbid and 6-month cognition were determined using the short form Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) which ranged from 1 to 5 (severe dementia). Multiple linear regression was performed to determine if ED delirium duration was associated with 6-month function and cognition adjusted for baseline OARS ADL and IQCODE, and other confounders. RESULTS: A total of 228 older ED patients were enrolled. Of the 105 patients who were delirious in the ED, 81 (77.1%) patients' delirium persisted into hospitalization. For every ED delirium duration day, the 6-month OARS ADL decreased by 0.63 points (95% CI: -1.01 to -0.24), indicating poorer function. For every ED delirium duration day, the 6-month IQCODE increased 0.06 points (95% CI: 0.01-0.10) indicating poorer cognition. CONCLUSIONS: Delirium in the ED is not a transient event and frequently persists into hospitalization. Longer ED delirium duration is associated with an incremental worsening of 6-month functional and cognitive outcomes.