The Confusion Assessment Method for the ICU-7 Delirium Severity Scale

A Novel Delirium Severity Instrument for Use in the ICU

Babar Khan, Anthony J. Perkins, Sujuan Gao, Siu Hui, Noll L. Campbell, Mark O. Farber, Linda L. Chlan, Malaz Boustani

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

OBJECTIVES:: Delirium severity is independently associated with longer hospital stays, nursing home placement, and death in patients outside the ICU. Delirium severity in the ICU is not routinely measured because the available instruments are difficult to complete in critically ill patients. We designed our study to assess the reliability and validity of a new ICU delirium severity tool, the Confusion Assessment Method for the ICU-7 delirium severity scale. DESIGN:: Observational cohort study. SETTING:: Medical, surgical, and progressive ICUs of three academic hospitals. PATIENTS:: Five hundred eighteen adult (≥ 18 yr) patients. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: Patients received the Confusion Assessment Method for the ICU, Richmond Agitation-Sedation Scale, and Delirium Rating Scale-Revised-98 assessments. A 7-point scale (0–7) was derived from responses to the Confusion Assessment Method for the ICU and Richmond Agitation-Sedation Scale items. Confusion Assessment Method for the ICU-7 showed high internal consistency (Cronbach’s α = 0.85) and good correlation with Delirium Rating Scale-Revised-98 scores (correlation coefficient = 0.64). Known-groups validity was supported by the separation of mechanically ventilated and nonventilated assessments. Median Confusion Assessment Method for the ICU-7 scores demonstrated good predictive validity with higher odds (odds ratio = 1.47; 95% CI = 1.30–1.66) of in-hospital mortality and lower odds (odds ratio = 0.8; 95% CI = 0.72–0.9) of being discharged home after adjusting for age, race, gender, severity of illness, and chronic comorbidities. Higher Confusion Assessment Method for the ICU-7 scores were also associated with increased length of ICU stay (p = 0.001). CONCLUSIONS:: Our results suggest that Confusion Assessment Method for the ICU-7 is a valid and reliable delirium severity measure among ICU patients. Further research comparing it to other delirium severity measures, its use in delirium efficacy trials, and real-life implementation is needed to determine its role in research and clinical practice.

Original languageEnglish (US)
JournalCritical Care Medicine
DOIs
StateAccepted/In press - Mar 3 2017

Fingerprint

Confusion
Delirium
Length of Stay
Odds Ratio
Hospital Mortality
Nursing Homes
Research
Critical Illness
Reproducibility of Results
Observational Studies
Comorbidity
Chronic Disease
Cohort Studies

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine

Cite this

The Confusion Assessment Method for the ICU-7 Delirium Severity Scale : A Novel Delirium Severity Instrument for Use in the ICU. / Khan, Babar; Perkins, Anthony J.; Gao, Sujuan; Hui, Siu; Campbell, Noll L.; Farber, Mark O.; Chlan, Linda L.; Boustani, Malaz.

In: Critical Care Medicine, 03.03.2017.

Research output: Contribution to journalArticle

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title = "The Confusion Assessment Method for the ICU-7 Delirium Severity Scale: A Novel Delirium Severity Instrument for Use in the ICU",
abstract = "OBJECTIVES:: Delirium severity is independently associated with longer hospital stays, nursing home placement, and death in patients outside the ICU. Delirium severity in the ICU is not routinely measured because the available instruments are difficult to complete in critically ill patients. We designed our study to assess the reliability and validity of a new ICU delirium severity tool, the Confusion Assessment Method for the ICU-7 delirium severity scale. DESIGN:: Observational cohort study. SETTING:: Medical, surgical, and progressive ICUs of three academic hospitals. PATIENTS:: Five hundred eighteen adult (≥ 18 yr) patients. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: Patients received the Confusion Assessment Method for the ICU, Richmond Agitation-Sedation Scale, and Delirium Rating Scale-Revised-98 assessments. A 7-point scale (0–7) was derived from responses to the Confusion Assessment Method for the ICU and Richmond Agitation-Sedation Scale items. Confusion Assessment Method for the ICU-7 showed high internal consistency (Cronbach’s α = 0.85) and good correlation with Delirium Rating Scale-Revised-98 scores (correlation coefficient = 0.64). Known-groups validity was supported by the separation of mechanically ventilated and nonventilated assessments. Median Confusion Assessment Method for the ICU-7 scores demonstrated good predictive validity with higher odds (odds ratio = 1.47; 95{\%} CI = 1.30–1.66) of in-hospital mortality and lower odds (odds ratio = 0.8; 95{\%} CI = 0.72–0.9) of being discharged home after adjusting for age, race, gender, severity of illness, and chronic comorbidities. Higher Confusion Assessment Method for the ICU-7 scores were also associated with increased length of ICU stay (p = 0.001). CONCLUSIONS:: Our results suggest that Confusion Assessment Method for the ICU-7 is a valid and reliable delirium severity measure among ICU patients. Further research comparing it to other delirium severity measures, its use in delirium efficacy trials, and real-life implementation is needed to determine its role in research and clinical practice.",
author = "Babar Khan and Perkins, {Anthony J.} and Sujuan Gao and Siu Hui and Campbell, {Noll L.} and Farber, {Mark O.} and Chlan, {Linda L.} and Malaz Boustani",
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AU - Khan, Babar

AU - Perkins, Anthony J.

AU - Gao, Sujuan

AU - Hui, Siu

AU - Campbell, Noll L.

AU - Farber, Mark O.

AU - Chlan, Linda L.

AU - Boustani, Malaz

PY - 2017/3/3

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N2 - OBJECTIVES:: Delirium severity is independently associated with longer hospital stays, nursing home placement, and death in patients outside the ICU. Delirium severity in the ICU is not routinely measured because the available instruments are difficult to complete in critically ill patients. We designed our study to assess the reliability and validity of a new ICU delirium severity tool, the Confusion Assessment Method for the ICU-7 delirium severity scale. DESIGN:: Observational cohort study. SETTING:: Medical, surgical, and progressive ICUs of three academic hospitals. PATIENTS:: Five hundred eighteen adult (≥ 18 yr) patients. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: Patients received the Confusion Assessment Method for the ICU, Richmond Agitation-Sedation Scale, and Delirium Rating Scale-Revised-98 assessments. A 7-point scale (0–7) was derived from responses to the Confusion Assessment Method for the ICU and Richmond Agitation-Sedation Scale items. Confusion Assessment Method for the ICU-7 showed high internal consistency (Cronbach’s α = 0.85) and good correlation with Delirium Rating Scale-Revised-98 scores (correlation coefficient = 0.64). Known-groups validity was supported by the separation of mechanically ventilated and nonventilated assessments. Median Confusion Assessment Method for the ICU-7 scores demonstrated good predictive validity with higher odds (odds ratio = 1.47; 95% CI = 1.30–1.66) of in-hospital mortality and lower odds (odds ratio = 0.8; 95% CI = 0.72–0.9) of being discharged home after adjusting for age, race, gender, severity of illness, and chronic comorbidities. Higher Confusion Assessment Method for the ICU-7 scores were also associated with increased length of ICU stay (p = 0.001). CONCLUSIONS:: Our results suggest that Confusion Assessment Method for the ICU-7 is a valid and reliable delirium severity measure among ICU patients. Further research comparing it to other delirium severity measures, its use in delirium efficacy trials, and real-life implementation is needed to determine its role in research and clinical practice.

AB - OBJECTIVES:: Delirium severity is independently associated with longer hospital stays, nursing home placement, and death in patients outside the ICU. Delirium severity in the ICU is not routinely measured because the available instruments are difficult to complete in critically ill patients. We designed our study to assess the reliability and validity of a new ICU delirium severity tool, the Confusion Assessment Method for the ICU-7 delirium severity scale. DESIGN:: Observational cohort study. SETTING:: Medical, surgical, and progressive ICUs of three academic hospitals. PATIENTS:: Five hundred eighteen adult (≥ 18 yr) patients. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: Patients received the Confusion Assessment Method for the ICU, Richmond Agitation-Sedation Scale, and Delirium Rating Scale-Revised-98 assessments. A 7-point scale (0–7) was derived from responses to the Confusion Assessment Method for the ICU and Richmond Agitation-Sedation Scale items. Confusion Assessment Method for the ICU-7 showed high internal consistency (Cronbach’s α = 0.85) and good correlation with Delirium Rating Scale-Revised-98 scores (correlation coefficient = 0.64). Known-groups validity was supported by the separation of mechanically ventilated and nonventilated assessments. Median Confusion Assessment Method for the ICU-7 scores demonstrated good predictive validity with higher odds (odds ratio = 1.47; 95% CI = 1.30–1.66) of in-hospital mortality and lower odds (odds ratio = 0.8; 95% CI = 0.72–0.9) of being discharged home after adjusting for age, race, gender, severity of illness, and chronic comorbidities. Higher Confusion Assessment Method for the ICU-7 scores were also associated with increased length of ICU stay (p = 0.001). CONCLUSIONS:: Our results suggest that Confusion Assessment Method for the ICU-7 is a valid and reliable delirium severity measure among ICU patients. Further research comparing it to other delirium severity measures, its use in delirium efficacy trials, and real-life implementation is needed to determine its role in research and clinical practice.

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