Delirium in the Emergency Department and Its Extension into Hospitalization (DELINEATE) Study: Effect on 6-month Function and Cognition

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.