Background:
Quantifying the severity of delirium is essential to advancing clinical care by improved understanding of delirium effect, prognosis, pathophysiology, and response to treatment.
Objective:
To develop and validate a new delirium severity measure (CAM-S) based on the Confusion Assessment Method.
Design:
Validation analysis in 2 independent cohorts.
Setting:
Three academic medical centers.
Patients:
The first cohort included 300 patients aged 70 years or older scheduled for major surgery. The second included 919 medical patients aged 70 years or older.
Measurements:
A 4-item short form and a 10-item long form were developed. Association of the maximum CAM-S score during hospitalization with hospital and posthospital outcomes related to delirium was evaluated.
Results:
Representative results included adjusted mean length of stay, which increased across levels of short-form severity from 6.5 days (95% CI, 6.2 to 6.9 days) to 12.7 days (CI, 11.2 to 14.3 days) (P for trend < 0.001) and across levels of long-form severity from 5.6 days (CI, 5.1 to 6.1 days) to 11.9 days (CI, 10.8 to 12.9 days) (P for trend < 0.001). Representative results for the composite outcome of adjusted relative risk of death or nursing home residence at 90 days increased progressively across levels of short-form severity from 1.0 (referent) to 2.5 (CI, 1.9 to 3.3) (P for trend < 0.001) and across levels of long-form severity from 1.0 (referent) to 2.5 (CI, 1.6 to 3.7) (P for trend < 0.001).
Limitation:
Data on clinical outcomes were measured in an older data set limited to patients aged 70 years or older.
Conclusion:
The CAM-S provides a new delirium severity measure with strong psychometric properties and strong associations with important clinical outcomes.
Primary Funding Source:
National Institute on Aging.
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Author, Article and Disclosure Information
From Beth Israel Deaconess Medical Center, Harvard Medical School, and Hebrew SeniorLife, Boston, Massachusetts; University of Massachusetts Medical School, Worcester, Massachusetts; and Warren Alpert Medical School of Brown University, Providence, Rhode Island.
Note: The CAM algorithm and instrument are copyrighted to the Hospital Elder Life Program, LLC (www.hospitalelderlifeprogram.org). Instructions and training manual are available at the Web site.
Acknowledgment: The authors thank the patients, families, physicians, and research staff who participated in the SAGES and Project Recovery studies and made this study possible. This work is dedicated to the memory of Joshua Bryan Inouye Helfand and Bradley Yoshio Inouye.
Grant Support: By National Institute on Aging grants P01AG031720 and K07AG041835 (Dr. Inouye), R01AG030618 and K24AG035075 (Dr. Marcantonio), and K01AG033643 (Dr. Saczynski). Dr. Inouye holds the Milton and Shirley F. Levy Family Chair.
Disclosures: None. Forms can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M13-1927.
Reproducible Research Statement: Study protocol, statistical code, and data set: Available on request from Dr. Inouye (e-mail, [email protected]
Corresponding Author: Sharon K. Inouye, MD, MPH, Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, 1200 Centre Street, Boston, MA 02459; e-mail, [email protected]
Current Author Addresses: Drs. Inouye and Schmitt, Mr. Kosar, and Ms. Puelle: Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, 1200 Centre Street, Boston, MA 02131.
Mr. Tommet: Butler Hospital, Duncan Building, 700 Butler Drive, Providence, RI 02912.
Dr. Saczynski: University of Massachusetts Medical School, Division of Geriatric Medicine, 377 Plantation Street, Biotech 4, Suite 315, Worcester, MA 01655.
Dr. Marcantonio: Harvard Medical School, Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215.
Dr. Jones: Butler Hospital, 345 Blackstone Boulevard, Providence, RI 02906.
Author Contributions:Conception and design: S.K. Inouye, E.R. Marcantonio, R.N. Jones.
Analysis and interpretation of the data: S.K. Inouye, C.M. Kosar, D. Tommet, E.R. Marcantonio, R.N. Jones.
Drafting of the article: S.K. Inouye.
Critical revision of the article for important intellectual content: S.K. Inouye, C.M. Kosar, E.M. Schmitt, M.R. Puelle, J.S. Saczynski, E.R. Marcantonio, R.N. Jones.
Final approval of the article: S.K. Inouye, C.M. Kosar, E.M. Schmitt, M.R. Puelle, J.S. Saczynski, E.R. Marcantonio, R.N. Jones.
Provision of study materials or patients: S.K. Inouye, E.R. Marcantonio.
Statistical expertise: S.K. Inouye, C.M. Kosar, D. Tommet, E.R. Marcantonio, R.N. Jones.
Obtaining of funding: S.K. Inouye, E.R. Marcantonio.
Administrative, technical, or logistic support: S.K. Inouye, C.M. Kosar, E.M. Schmitt, M.R. Puelle.
Collection and assembly of data: S.K. Inouye, C.M. Kosar, D. Tommet, E.M. Schmitt, E.R. Marcantonio.
* Drs. Marcantonio and Jones contributed equally as co–senior authors.
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