Exploring Delirium's Heterogeneity: Association Between Arousal Subtypes at Initial Presentation and 6-Month Mortality in Older Emergency Department Patients.
OBJECTIVE
To determine how delirium subtyped by level of arousal at initial presentation affects 6-month mortality.


METHODS
This was a preplanned secondary analysis of two prospective cohort studies.


METHODS
Academic tertiary care emergency department (ED).


METHODS
1,084 ED patients who were 65 years old or older.


METHODS
At the time of enrollment, trained research personnel performed the Confusion Assessment Method for the Intensive Care Unit and the Richmond Agitation Sedation Score to determine delirium and level of arousal, respectively. Patients were categorized as having no delirium, delirium with normal arousal, delirium with decreased arousal, or delirium with increased arousal. Death was ascertained by medical record review and the Social Security Death Index. Cox proportional hazard regression was used to analyze the association between delirium arousal subtypes and 6-month mortality.


RESULTS
Delirium with normal arousal was the only subtype that was significantly associated with increased 6-month mortality (hazard ratio [HR]: 3.1, 95% confidence interval [CI]: 1.3-7.4) compared with the no delirium group after adjusting for confounders. The HRs for delirium with decreased and increased arousal were 1.4 (95% CI: 0.9-2.1) and 1.3 (95% CI: 0.3-5.4), respectively.


CONCLUSIONS
Delirious ED patients with normal arousal at initial presentation had a threefold increased hazard of death within 6 months compared with patients without delirium. There was a trend towards increased hazard of death in delirious ED patients with decreased arousal, but this relationship did not reach statistical significance. These data suggest that subtyping delirium by arousal may have prognostic value but requires confirmation with a larger study.
Center for Quality Aging, Vanderbilt University School of Medicine, Nashville, TN; Department of Emergency Medicine, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN; Center for Health Services Research, Vanderbilt University School of Medicine, Nashville, TN. Electronic address: jin.h.han@vanderbilt.edu.
Jin H
JH
Han
Center for Quality Aging, Vanderbilt University School of Medicine, Nashville, TN; Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University School of Medicine, Nashville, TN; Center for Health Services Research, Vanderbilt University School of Medicine, Nashville, TN.
Nathan E
NE
Brummel
Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN.
Rameela
R
Chandrasekhar
Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN.
Jo Ellen
JE
Wilson
Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN.
Xulei
X
Liu
Center for Quality Aging, Vanderbilt University School of Medicine, Nashville, TN; Section of Hospital Medicine, Vanderbilt University School of Medicine, Nashville, TN; Center for Health Services Research, Vanderbilt University School of Medicine, Nashville, TN; Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Tennessee Valley Health Care Center, Nashville, TN.
Eduard E
EE
Vasilevskis
Center for Quality Aging, Vanderbilt University School of Medicine, Nashville, TN; Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University School of Medicine, Nashville, TN; Center for Health Services Research, Vanderbilt University School of Medicine, Nashville, TN; Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Tennessee Valley Health Care Center, Nashville, TN.
Timothy D
TD
Girard
Division of Geriatrics, Vanderbilt University School of Medicine, Nashville, TN.
Maria E
ME
Carlo
Division of General Internal Medicine and Public Health, Vanderbilt University School of Medicine, Nashville, TN; Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Tennessee Valley Health Care Center, Nashville, TN.
Robert S
RS
Dittus
Center for Quality Aging, Vanderbilt University School of Medicine, Nashville, TN; Division of General Internal Medicine and Public Health, Vanderbilt University School of Medicine, Nashville, TN; Division of Geriatrics, Vanderbilt University School of Medicine, Nashville, TN; Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Tennessee Valley Health Care Center, Nashville, TN.
John F
JF
Schnelle
Center for Quality Aging, Vanderbilt University School of Medicine, Nashville, TN; Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University School of Medicine, Nashville, TN; Center for Health Services Research, Vanderbilt University School of Medicine, Nashville, TN; Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Medical Center, Tennessee Valley Health Care Center, Nashville, TN.
E Wesley
EW
Ely
D000368:Aged; D000369:Aged, 80 and over; D001143:Arousal / Q000502:physiology*; D003693:Delirium / Q000145:classification / Q000401:mortality / Q000503:physiopathology; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies
Delirium; arousal; mortality; subtypes