New scoring system accurately rates delirium severity

The CAM-S, a new delirium severity measure based on the Confusion Assessment Method, accurately evaluated patients with delirium, according to a study published in the Annals of Internal Medicine.

The Confusion Assessment Method (CAM) is a standardized measure used to screen for delirium. Sharon K. Inouye, MD, of the Institute for Aging Research, and colleagues developed a new CAM-based scoring system that includes a four-item short form and a 10-item long form for delirium severity. The short form is based on four features from the CAM algorithm: acute onset or symptom fluctuation, inattention, disorganized thinking and altered level of consciousness. Symptoms are rated either 0 (absent), 1 (mild) or 2 (marked). The sum of ratings ranges from 0 to 7, with 7 being most severe.

The long form of CAM-S is based on 10 features: acute onset or symptom fluctuation, inattention, disorganized thinking, altered level of consciousness, disorientation, memory impairment, perceptual disturbances, psychomotor agitation, psychomotor retardation and sleep-wake cycle disturbance. Symptoms are rated 0 to 2, like the short form CAM-S. The sum of long form symptoms ranges from 0 to 19, with 19 indicating highest severity.

To determine the new system’s accuracy, researchers conducted a study with two cohorts consisting of 300 patients aged 70 years and older with little to no risk for delirium; and 919 patients aged 70 years and older who were undiagnosed, but had a moderate to high risk for delirium. Participants were interviewed daily during hospitalization using the CAM-S scoring system and other measures of confusion and cognitive functioning.

The overall agreement for short form and long form scoring was 98% and 97%. The CAM-S showed moderate to high agreement with other daily cognitive measures, according to the study.

In the first cohort, the CAM-S agreement was highest with the daily confusion rating and brief cognitive screen. In the second cohort, the CAM-S was most accurate with the daily confusion rating and the Mini-Mental State Examination score.

“The CAM-S provides a new scoring method with strong psychometric properties to add to the armamentarium of delirium measures. This measure may serve as a primary outcome for clinical trials and studies of the pathophysiology or prognosis of delirium. We hope that the availability of this measure will serve to facilitate critically needed studies of delirium and its outcomes and ultimately lead to improved quality of life for older persons and their families,” the researchers concluded.