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BOSTON – As many as one in 10 older adults seen in hospital EDs in the United States experience delirium, but, in too many cases, the condition goes unrecognized, partly because of a lack of accurate screening instruments.
Now, a solution appears to be in sight for that issue, documented earlier this year by researchers from Indiana University and the Regenstrief Institute.
A 3-minute diagnostic assessment for delirium has been developed by investigators at Beth Israel Deaconess Medical Center (BIDMC) in Boston, and the instrument appears to be extremely accurate in identifying the condition in a group of older hospital patients.
In the study, which appeared recently in the Annals of Internal Medicine, the authors report that the assessment, the 3-Minute Diagnostic Interview for CAM-Defined Delirium (3D-CAM), detected delirium with more than 90% specificity and sensitivity when compared with a reference standard.
The 3D-CAM’s high rates of accuracy in identifying delirium in patients who have dementia were especially significant, because that group is harder to diagnose, according to the report.
"Prompt recognition of delirium is the first step to timely evaluation and treatment, preventing complications and keeping older patients safe while in the hospital," says lead author Edward Marcantonio, MD, SM, director of the Aging Research Program in the Division of General Medicine and Primary Care at BIDMC and professor of medicine at Harvard Medical School. "As growing numbers of older adults are being hospitalized, it's critically important that doctors, nurses and other hospital care providers be able to recognize delirium. We wanted to develop a brief and simple method to make this easier to accomplish, and we are extremely happy with the 3D-CAM results. It appears that this easy-to-administer interview could significantly improve detection of this common and morbid condition in vulnerable older hospital patients. "
Background in the article points out that delirium affects 30-to-40% of older medical patients and between 15-and-50% of older surgical patients, yet remains under-recognized. In most clinical settings, average detection rates are only 12-to-35%. Low recognition is especially the case for patients with hypoactive delirium because they tend to be quiet and lethargic, as opposed to agitated dementia patients who disrupt EDs and other medical settings.
The CAM algorithm was originally developed in 1990 by the study's senior author Sharon K. Inouye, MD, MPH, director of the Aging Brain Center in the Institute for Aging Research at Hebrew Senior Life and HMS Professor of Medicine in the Division of Gerontology at BIDMC. To date, the CAM has been translated into more than a dozen languages and used in more than 4,000 original studies. It requires that the assessor determine the presence or absence of four key features of delirium:
To be diagnosed with delirium, a patient must have features 1 and 2 and either 3 or 4.
"We have found that there are many different cognitive tests that the person rating the CAM can use to assess for these four features, and we've shown that the quality of the assessment makes a big difference in the accuracy of identification of delirium," Inouye explained. "The 3D-CAM is a major advance since it provides a brief, easy-to-administer approach that operationalizes the CAM algorithm in three minutes, and provides highly accurate results compared to a gold standard clinical assessment."
An original list of 160 questions and observations was whittled down to 20 items to develop the 3D-CAM assessment tool. It then was tested in a prospective validation study that enrolled 201 patients older than 75 who were hospitalized in BIDMC's General Medicine Service between 2010 and 2012.
The authors first conducted a 60- to 90-minute "gold standard" clinical assessment for delirium and dementia, in which an experienced clinician conducted a full patient evaluation including a cognitive exam, a review of the patient's medical records and conversations with the patient's nurse and family caregiver. Whether each patient was diagnosed with delirium was then determined by an expert panel.
The gold standard assessment determined that 42 of 201 participants (21%) had delirium, with most of them, 88%, exhibiting the hypoactive type. At the same time, 56 patients (28%) were determined to have had dementia prior to being admitted to the hospital; some had both delirium and dementia.
Research assistants then administered the 3D-CAM assessment without knowledge of the gold-standard results.