Letter to the Editor
Confusion Assessment Method (CAM) Indicators When CAM Positivity in 647 Individuals Has Good Outcome
Article first published online: 11 JAN 2013
© 2013, Copyright the Authors Journal compilation © 2013, The American Geriatrics Society
Journal of the American Geriatrics Society
Volume 61, Issue 1, page 173, January 2013
How to Cite
Regal, P. (2013), Confusion Assessment Method (CAM) Indicators When CAM Positivity in 647 Individuals Has Good Outcome. Journal of the American Geriatrics Society, 61: 173. doi: 10.1111/jgs.12054
- Issue published online: 11 JAN 2013
- Article first published online: 11 JAN 2013
To the Editor:
Huang and colleagues assembled the dream team of researchers of delirium in elderly adults to match features from the medical history, physical examination, and cognitive behavioral assessment with the four elements of the Confusion Assessment Method (CAM). We found this analysis highly useful. The main premise of their study was that the CAM is the criterion standard for identifying delirium in elderly adults. This clearly was true when the CAM was developed in 1990. In 2011–2012, this premise is no longer true in the acute geriatric unit of our hospital and we suspect in regions with a national health service providing acute care for elderly adults, such as Australia, where we work. This is no more surprising than saying that a prognostic system for pulmonary tuberculosis devised in 1930 before streptomycin, isoniazid, or rifampicin is not valid since antituberculous drugs were implemented. We analyzed 647 individuals with a mean age of 84 admitted to our acute care for the elderly unit in Australia from January 2011 to June 2012; 76% were admitted directly to the geriatric unit, and 11% were transferred 8 days or more after admission. Whenever an individual answered incorrectly during cognitive assessment, the remaining questions were given with a portable amplifier with headphones. This helps to exclude impaired hearing as the cause of inattention, disorientation, or poor memory. The 60 CAM-positive subjects (9.3%) had the same mortality at discharge and at 30, 90, 180, and 365 days and the same rate of returning home versus to a hostel (low-level care) or nursing home (high-level care) as the 587 CAM-negative subjects. In July 2012, a prospective randomized controlled trial comparing acute care for the elderly with general medicine for CAM-positive elderly adults was commenced in an emergency department (Central Coast Australia Delirium Intervention Study (CADIS; registered in ClinicalTrials.gov and Australian New Zealand Clinical Trials Registry)). In the general medicine group, the diagnosis of delirium is written in the medical chart every day, and a research assistant measures the delirium index and digit span daily, recording results in the medical chart so that the general medicine team can assess progress in treating delirium. CADIS will compare the CAM with the Regal criteria for grading delirium against two hard outcomes: mortality at discharge and 30, 90, 180, and 365 days and return home rate. The Regal method for grading delirium has many elements distinct from the CAM. First, it mandates assembling previous assessments from geriatricians, neurologists, neuropsychologists, psychiatrists, and others assessing cognition and behavior before the current illness. Finding the most recent measurement and calculating the difference from the current value is essential to distinguish delirium from dementia or other chronic cognitive disorders. Second, it mandates hearing assessment using the whisper test, followed by correction of hearing impairment using a portable amplifier with headphones. Third, it sets a specific target of at least 30% decline from a recent test in attention tests such as digit span forward. (If there is no recent test, then a minimum 30% improvement on resolution of delirium is required.) Rapid improvement is typically found within 7 days. Fourth, it mandates at least a 30% decline in selective instrumental activities of daily living (SIADLs), which include activities not affected by lower limb and mobility problems such as hip fracture or hemiplegic stroke. Examples of SIADLs are reading maps or a daily newspaper, performing crossword puzzles, and making change with coins. IADLs are a useful marker of functional cognition in dementia and mild cognitive impairment. Functional decline is an important element in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnosis of dementia; functional decline is also important to distinguish delirium from psychosis without inattention. Other acute care for the elderly units should compare the outcomes of CAM-positive and -negative individuals and compare these with grade of delirium according to the Regal criteria.
Presented in part at the Australian Delirium Society conference, Sydney, Australia, May 1, 2012, and the International Psychogeriatric Association Conference, Cairns, Australia, September 10, 2012.
Conflict of Interest: Paul Regal declares no conflict of interest with employment, affiliations, grants, funding, honoraria, speaker's forum, consultancy, stocks, royalties, expert testimony, board membership, patents, or personal relationships.
Author Contributions: Paul Regal was responsible for the study concept, study design, acquisition of subjects, data management, analysis, interpretation, and preparation of the manuscript.
Sponsor's Role: No sponsor.
- 4Hearing impairment, amplifiers and digit span. Am J Geriatr Psychiatry 2012. In press..