Clinical deterioration in older adults with delirium during early hospitalisation: a prospective cohort study

OBJECTIVES: To measure the prevalence and incidence of delirium in older adults as they transition from the emergency department (ED) to the inpatient ward, and to determine the association between delirium during early hospitalisation and subsequent clinical deterioration. DESIGN: Prospective cohort study. SETTING: Urban tertiary care hospital in Bronx, New York. PARTICIPANTS: Adults aged 65 years or older admitted to the inpatient ward from the ED (n=260). MEASUREMENTS: Beginning in the ED, delirium was assessed daily for 3 days, using the Confusion Assessment Method for the Intensive Care Unit. OUTCOMES: (1) Clinical deterioration, defined as unanticipated intensive care unit (ICU) admission or in-hospital death (primary outcome); (2) decline in discharge status, defined as discharge to higher level of care, hospice or in-hospital death. RESULTS: 38 of 260 participants (15%) were delirious at least once during the first 3 days of hospitalisation. Of the 29 (11%) patients with delirium in the ED (ie, hospital day 1), delirium persisted into hospital day 2 in 72% (n=21), and persisted for all 3 days in 52% (n=15). In multivariate analyses, as little as 1 episode of delirium during the first 3 days was associated with increased odds of unanticipated ICU admission or in-hospital death (adjusted OR 8.07 (95% CI 1.91 to 34.14); p=0.005). Delirium that persisted for all 3 days was associated with a decline in discharge status, even after adjusting for factors such as severity of illness and baseline cognitive impairment (adjusted OR 4.70 (95% CI 1.41 to 15.63); p=0.012). CONCLUSIONS: Delirium during the first few days of hospitalisation was associated with poor outcomes in older adults admitted from the ED to the inpatient ward. These findings suggest the need for serial delirium monitoring that begins in the ED to identify a high-risk population that may benefit from closer follow-up and intervention.