The investigators conducted a systematic review of research on biomarkers linked to delirium and report that clinicians and researchers are not routinely using these chemical indicators found in the blood as tools to diagnose patients with delirium, to assess the severity of the condition or potentially to inform the development of new therapies to treat it.

"These biomarkers linked to delirium provide us with a window to the disease process. With a clearer understanding of underlying mechanisms we can do a better job at recognizing and managing delirium and ultimately of developing therapies," said Regenstrief Institute investigator Babar Ali Khan, M.D., assistant professor of medicine at the IU School of Medicine, who led the study.

The new study, "Biomarkers for Delirium -- A Review" appears in a Nov. 14, 2011, supplement of the Journal of the American Geriatrics Society devoted to delirium.

Delirium is known to be a predictor of decreased life span and higher health care costs. It is estimated by the American Delirium Society that more than 60 percent of patients with delirium are not diagnosed. Currently, there is no U.S. Food and Drug Administration-approved drug therapy for the prevention or management of delirium.

The authors analyzed all relevant peer-reviewed studies of delirium activity markers published in English since 2000 and concluded that while proper use of a patient's chemical markers might help his or her doctors identify delirium and predict its course, these biological tools are not being used currently in routine clinical care.

"Future research on delirium should assess risk markers through serial blood draws, comparing the levels during the delirious episode and then follow up with levels after delirium resolution," Dr. Khan said. "Important factors such as age, race, baseline cognitive impairment and severity of illness should be considered in the final analysis. This will not only help individual patients, it will help pave the way forward for development of disease-modifying drugs."

Dr. Khan is a pulmonary/critical care physician and director of a new follow-up clinic for intensive care unit patients: the Critical Care Recovery Center at Wishard Health Services. He estimates that 80 percent of critically ill patients in the United States develop delirium.

Delirium is a state of confusion in which the individual has undergone a sudden alteration of mental status. Delirium is not dementia, but individuals with dementia are more susceptible to developing delirium during hospitalization than individuals without dementia.

"Having delirium prolongs the length of a hospital stay, increases the risk of post-hospitalization transfer to a nursing home and doubles the risk of death. We need to identify those who have delirium and to develop safe and effective ways to prevent and treat delirium. Biomarkers appear to be an important tool," said Regenstrief Institute investigator Malaz Boustani, M.D., senior author of the study. Dr. Boustani is a Regenstrief Institute investigator, associate professor of medicine at the IU School of Medicine and director of the Healthy Aging Brain Center at Wishard Health Services.

Authors of the study in addition to Dr. Khan and Dr. Boustani are Mohammed Zawahiri, M.D.,of the Regenstrief Institute and Noll L. Campbell, Pharm.D.,of the Regenstrief Institute, Wishard Health Services and the Purdue University School of Pharmacy. All four authors are with the IU Center for Aging Research.

The Regenstrief Institute and the IU School of Medicine are on the campus of Indiana University-Purdue University Indianapolis.

The study was funded by grants from the National Institute on Aging and the National Institute on Mental Health.

Note: If no author is given, the source is cited instead.

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• Dementia
• Mental confusion
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• Psychosis