3-minute assessment for delirium may improve diagnosis

A 3-minute assessment for delirium as defined by the Confusion Assessment Method (CAM) may help improve recognition of the disorder, according to a new study.

Researchers derived the assessment, called 3D-CAM, by identifying 20 items that best operationalized the 4 diagnostic features of CAM. For prospective validation, trained research assistants at 4 general medicine units administered 3D-CAM assessments to 201 inpatients 75 years of age or older. Clinicians independently performed extensive assessments that included interviews with patients and families and medical record reviews. An expert panel then examined these data to determine the presence or absence of delirium and dementia; this was the reference standard. The researchers compared the 3D-CAM diagnosis of delirium with the reference standard for all patients and for patients with and without dementia. Results appeared in the Oct. 21 Annals of Internal Medicine.

Patients in the prospective validation study had a mean age of 84 years, and 28% had dementia at baseline, according to the expert panel. The reference standard assessment found that 21% of patients had delirium, and of these, 88% had hypoactive or normal psychomotor features. The median time to administer the 3D-CAM was 3 minutes (interquartile range, 2 to 5 minutes).

Twenty-four percent of patients were found to have delirium, according to the 3D-CAM. The 3D-CAM had a sensitivity of 95% (95% CI, 84% to 99%) and a specificity of 94% (95% CI, 90% to 97%) in all patients and also performed well in subgroups of patients with and without dementia (sensitivity, 96% [95% CI, 82% to 100%] and 93% [95% CI, 66% to 100%], respectively; specificity, 86% [95% CI, 67% to 96%] and 96% [95% CI, 91% to 99%], respectively).

The authors noted that the study was performed in only 1 medical center in only medical patients and was based on a single hospital day. However, they concluded that the 3D-CAM was “a brief, highly reproducible, and valid method for diagnosing delirium using the CAM algorithm,” with high sensitivity and specificity compared to the reference standard. “Given these characteristics, the 3D-CAM could be an important component of future efforts to improve systematic case-finding of delirium in high-risk older adults,” the authors wrote. “Further research will focus on developing the optimal strategies for translating the 3D-CAM into routine care and determining whether improved detection of delirium can result in improved outcomes for vulnerable hospitalized older persons.”