The CAM-S: development and validation of a new scoring system for delirium severity in 2 cohorts

Ann Intern Med. 2014 Apr 15;160(8):526-533. doi: 10.7326/M13-1927.

Abstract

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.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Activities of Daily Living
  • Aged
  • Aged, 80 and over
  • Cognition Disorders / diagnosis
  • Delirium / diagnosis*
  • Delirium / therapy
  • Female
  • Hospital Costs
  • Humans
  • Length of Stay
  • Male
  • Nursing Homes
  • Psychological Tests*
  • Psychometrics
  • Severity of Illness Index