OREGON STATE UNIVERSITY

Simple test may help address $150 billion problem of post-operative delirium

09/19/2016

PORTLAND, Ore. – Researchers at VA Portland Health Care System (VAPORHCS), in collaboration with Oregon State University and Oregon Health & Science University, have identified a simple test that takes about 2-3 minutes and can predict which surgical candidates are most at risk of delirium, a common complication following surgery in older patients.

Delirium, or acute confusion and disorientation, has become a $150 billion national problem.

After surgery, delirium can lead to slower recovery, a long-term worsening of memory and thinking, and even death - while significantly increasing health care costs. Identification of those most at risk could help guide decisions about whether or not to have surgery, and allow prompt, low-cost interventions after surgery to help prevent this problem.

The findings were just published in the Journal of the American Geriatric Society by doctors from the Veterans Affairs Research Department in Portland, who led and funded the study, and worked with partnering investigators from OSU and OHSU.

“Before this study, identifying people at risk for delirium following surgery required complicated or time-consuming evaluations,” said Dr. Sarah Goodlin, the lead VAPORHCS investigator for the study.

“We try to avoid delirium whenever possible, but our tools have been limited. Now we believe we can identify people at high risk and help physicians make informed decisions with their patients about the hazards and benefits of pursuing elective surgery.”

Further research will be needed to confirm the findings and broaden them to other groups, Goodlin said. This research, for instance, was done with 76 veterans age 65 or older who were almost exclusively male.

Several tests have been available for some time to test memory and mental function. One test, a brief screening tool called the “Mini-Cog,” was developed by Dr. Soo Borson at the University of Washington to detect dementia.

The current research found that one way of using and scoring the Mini-Cog offered high predictive accuracy of delirium following elective surgery with major anesthesia. Other tests and patient factors did not really improve the predictive risk of delirium.

“We wanted to identify a tool that was simple and accurate, and the Mini-Cog does that,” said Amber An DO, who designed the study with Goodlin during her geriatric medicine fellowship.

The Mini-Cog may help to prevent this problem, said David Lee, an assistant professor in the OSU/OHSU College of Pharmacy, and co-author on the study.

“This is such a serious issue,” Lee said. “Delirium can cause serious health and cognitive problems, begin a process of decline that can lead to dementia, and can almost double the cost of a hospital stay.”

However, the researchers pointed out in their study that medical care is more effective at preventing delirium, especially in people at moderate risk, than in treating it once it develops. That makes a predictive tool all the more helpful. More research is needed to understand steps that can be taken during or following surgery to decrease post-operative delirium rates.

The Mini-Cog test itself is quick and simple, can be done in any language and has no ethnic, educational or cultural barriers. A person is told three ordinary words and asked to repeat them, such as “apple,” “watch” and “penny.” They are then asked to draw a simple clock face, including the numbers and hands set to a specific time. Finally, they are asked to repeat the three words they were told. That’s all there is to the test.

The authors of the current study scored the Mini-Cog from 0-5. A person gets 2 points for correctly drawing a clock and time; and 1 point each for recalling the three words.

According to this research, a person with a score of 0-1 had a 50 percent or greater probability of post-operative delirium. Those with a score of 3 had a 20 percent probability; a score of 4 a 13 percent probability; and a score of 5 less than 5 percent probability of delirium after surgery.

The incidence of delirium ranges from 7-10 percent in older adults after simple elective surgery, rising to at least half of older adults undergoing emergency, cardiac or orthopedic surgery. Individuals who develop delirium are more likely to be debilitated, require skilled nursing care, and die in the year after surgery.

Factors that have been significantly associated with delirium risk include existing dementia, depression, use of multiple medications, sensory impairment, and the use of alcohol or psychoactive drugs.

 

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