Rationale: Delirium is a frequent occurrence in older intensive care unit (ICU) patients, but the importance of the duration of delirium in contributing to adverse long-term outcomes is unclear. Objectives: To examine the association of the number of days of ICU delirium with mortality in an older patient population. Methods: We performed a prospective cohort study in a 14-bed ICU in an urban acute care hospital. The patient population comprised 304 consecutive admissions 60 years of age and older. Measurements and Main Results: The main outcome was 1-year mortality after ICU admission. Patients were assessed daily for delirium with the Confusion Assessment Method for the ICU and a validated chart review method. The median duration of ICU delirium was 3 days (range, 1-46 d). During the follow-up period, 153 (50%) patients died. After adjusting for relevant covariates, including age, severity of illness, comorbid conditions, psychoactive medication use, and baseline cognitive and functional status, the number of days of ICU delirium was significantly associated with time to death within 1 year post-ICU admission (hazard ratio, 1.10; 95% confidence interval, 1.02-1.18). Conclusions: Number of days of ICU delirium was associated with higher 1-year mortality after adjustment for relevant covariates in an older ICU population. Investigations should be undertaken to reduce the number of days of ICU delirium and to study the impact of this reduction on important health outcomes, including mortality and functional and cognitive status.
Objective
There is a high prevalence of delirium in older medical intensive care unit (ICU) patients and delirium is associated with adverse outcomes. We need to identify modifiable risk factors for delirium in the ICU, such as medication use. The objective of this study was to examine the impact of benzodiazepine or opioid use on the duration of ICU delirium in an older medical population.
Design
Prospective cohort study.
Setting
Fourteen-bed medical intensive care unit in an urban university teaching hospital.
Patients
304 consecutive admissions age 60 and older.
Interventions
None
Main Outcome Measurements
The main outcome measure was duration of ICU delirium, specifically the first episode of ICU delirium. Patients were assessed daily for delirium with the Confusion Assessment Method for the ICU (CAM-ICU) and a validated chart review method. Our main predictor was the receipt of benzodiazepines or opioids during ICU stay. A multivariable model was developed using Poisson rate regression.
Results
Delirium occurred in 239 of 304 patients (79%). The median duration of ICU delirium was 3 days with a range of 1-33 days. In a multivariable regression model receipt of a benzodiazepine or opioid (RR, 1.64, 95% CI, 1.27-2.10) was associated with increased delirium duration. Other variables associated with delirium duration in this analysis include preexisting dementia (RR, 1.19, 95% CI 1.07-1.33), receipt of haloperidol (RR, 1.35, 95% CI, 1.21-1.50), and severity of illness (RR, 1.01, 95% CI, 1.00-1.02).
Conclusions
The use of benzodiazepines or opioids in the ICU is associated with longer duration of a first episode of delirium. Receipt of these medications may represent modifiable risk factors for delirium. Clinicians caring for ICU patients should carefully evaluate the need for benzodiazepines, opioids and haloperidol.
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