After Hospitalization, Mental Trouble for Elderly Patients

Posted on March 29, 2012

Many older people fear that a hospital stay could leave them even more disabled than they were before. Unfortunately, there’s new reason to believe this fear is justified. Elderly patients who are hospitalized are at much higher risk of cognitive problems afterward, according to a study published on Wednesday in the journal Neurology.

The cause is unclear: Both the illness that brought the patient to the hospital and the treatments received there may contribute. But the risk appeared to last for years, said Robert Wilson, lead author of the report and a professor of neurological and behavioral sciences at Rush University Medical Center in Chicago.

Dr. Wilson and his colleagues examined data on 1,335 people age 65 and older participating in the Chicago Health and Aging Project, a long-term study of chronic illness in three racially mixed Chicago neighborhoods. All of the patients were hospitalized at some point between January 1993 and December 2007. They were interviewed every three years and given tests of mental status. At least one interview occurred before a hospitalization and two interviews after, allowing changes in mental status to be tracked over time.

The researchers found that the rate of cognitive decline in older patients more than doubled after a hospital stay, generally affecting thinking and memory across the board. Before these older people were admitted, mental test scores slipped 0.031 units per year on average; after a hospitalization, the decline was 0.075 units annually on average.

“Essentially, it’s as if people became 10 years older, from a cognitive standpoint, than they actually were before a hospitalization,” Dr. Wilson said.
Especially vulnerable to this effect were patients with more serious illnesses who stayed in the hospital for longer periods of time, and patients who started experiencing worsening memory and thinking problems before they were admitted.

“We think that a hospital stay can help unmask and accelerate previously unidentified cognitive problems,” Dr. Wilson said.

Not every older patient who goes to the hospital will experience these kinds of issues, Dr. Wilson added; many return home after an acute-care stay without any kind of impairment.

It’s already known that a hospital stay can interfere with an older person’s physical functioning and ability to perform the so-called activities of daily living — bathing, toileting, dressing and so on — said Dr. Kenneth Covinsky, professor of geriatrics at the University of California, San Francisco.

“What this new research does is add another layer and show that there’s also this cognitive loss that’s occurring,” he said. “While we suspected this before, there wasn’t strong enough data to firmly establish it before this study.”

What explains the loss? Dr. Malaz Boustani, associate professor of medicine at Indiana University, suspects the culprit is delirium — an abrupt change in mental status occurring in up to 20 percent of hospital patients, who become very confused, disoriented, agitated or unresponsive and withdrawn.

Delirium once was thought to be transient. Now, it’s increasingly regarded as a form of brain injury that can “change the trajectory of your cognitive status,” said Dr. Boustani. “Even when you supposedly recover, there’s a residual effect.”

Dr. Boustani and colleagues at Indiana University are searching for the underlying mechanism, and think it may involve low oxygen levels or inflammation that kills neurons in the brain. But these are hypotheses only.

“Is this cognitive insult caused by the illness that brought the patient to the hospital, or by what we do in the hospital?” Dr. Boustani asked. “It appears to be both.”

Of special concern are medications that acutely ill patients receive in settings such as intensive care.

“I worry a lot as an I.C.U. physician that there are long-lasting effects of the medications we use,” said Dr. Catherine Hough, an associate professor of medicine at the University of Washington. “Unfortunately, the cognitive effects of these medications have rarely been studied.”

Dr. Hough was an author of a study, published in 2010 in The Journal of the American Medical Association, that found that older people hospitalized for non-critical conditions were more likely to receive a new diagnosis of dementia. The paper also documented a link between critically ill patients and cognitive decline.

Other factors that might contribute long-term to cognitive problems include tiny, undetectable strokes that afflict older patients, uncontrolled blood sugar, or a lack of stimulating mental activity while people are in the hospital, Dr. Hough and other experts suggested.

Since there are ways of preventing delirium and addressing these other concerns, it’s likely that some of the cognitive decline in older hospital patients is preventable, Dr. Wilson said.

For families, the new study adds to evidence that hospitalizations can be a seminal event that changes an older person’s functioning going forward.

“Know that when your elderly parent is coming out of the hospital, this has the potential to be a very vulnerable period,” Dr. Covinsky said. “Whatever need your parent had prior to the hospitalization, there’s a good chance they may change and that more support will be required.”

By JUDITH GRAHAM

Originally published at newoldage.blogs.nytimes.com