TUESDAY, June 19 (HealthDay News) -- For people with Alzheimer's disease, a stay in the hospital could lead to accelerated mental decline and increase the risk of going into a nursing home or dying, according to a new study.

The investigators also found that those who experienced delirium, which is a state of heightened confusion or unusual mood or behavior, while in the hospital were even less likely to go back to the way things were after hospital discharge.

For the study, researchers followed nearly 800 people with mild Alzheimer's disease, about half of whom went to the hospital over the course of the study period due to falls, infections or other problems. Being hospitalized was associated with nearly twice the likelihood of having a poor outcome, including mental decline and death, and being delirious while hospitalized increased the risk by about 12 percent.

The study was published in the June 19 online issue of Annals of Internal Medicine.

Previous research found that hospitalization and delirium can speed mental slipping in older adults and patients with Alzheimer's, but the current study is the first to dissect the risks associated with having delirium on top of being hospitalized on outcomes including institutionalization and death, according to background information in the study.

"Delirium can be quite a problem for patients even with mild Alzheimer's disease, and preventing it may be a more effective treatment strategy than the current medications," said Dr. Tamara Fong, an assistant professor of neurology at Harvard Medical School and lead author of the study.

A number of steps can help prevent delirium in hospitalized patients, such as visiting with a family member or a familiar person, having eyeglasses or hearing aids available, getting out of bed for walks and not taking medications such as painkillers that can worsen confusion.

"There are some people who advocate keeping older people out of the hospital and treating them at home. This is an interesting [idea] because it does reduce the chance of delirium and reduces health care costs in other ways," Fong said.

People with Alzheimer's disease are three times as likely to spend time in the hospital. Between 20 percent and 40 percent of Alzheimer's patients are hospitalized each year for an average of about four days, the study authors noted.

The current study included 771 patients with mild Alzheimer's enrolled at Massachusetts Alzheimer's Disease Research Center where they were regularly evaluated for neurological function. Most of the patients were either living on their own or with family.

Among this group, 367 patients were hospitalized within 18 months of a research center visit and 194 of these patients had delirium during hospitalization. Delirium was the reason for hospitalization in only 4 percent of cases; the most common causes were fainting, falls, heart problems and abdominal pain.

The study authors found that 41 percent of the patients who were hospitalized with delirium had accelerated mental decline during the year following hospitalization, which they measured using a memory and concentration test. In comparison, only 23 percent of hospitalized patients without delirium and 26 percent of patients who were not hospitalized experienced increased mental decline during this time.

Whereas hospitalization on its own did not appear to drive up the risk of mental decline, delirium among patients who were hospitalized increased the risk by 20 percent.

Most Alzheimer's patients eventually have to be institutionalized, and many of them need help within five to 10 years of diagnosis, Fong said. Patients live between eight and 10 years on average after being diagnosed, and as Fong pointed out, usually die because of complications such as pneumonia.

In this study, the risk of going into a nursing home and dying in the year following hospitalization was higher for both groups of hospitalized patients. Those who developed delirium were 9.3 times more likely than nonhospitalized patients to be institutionalized and 5.4 times more likely to die, while those who were hospitalized and did not have delirium were 6.9 and 4.7 times more likely, respectively.

The researchers took into account the fact that hospitalized patients were generally older and sicker than patients who did not have to go to the hospital during the study.

However, the fact that the study involved only one research center and that the participants were predominantly white makes it harder to say the outcomes associated with hospitalization and delirium could apply to the overall population, Fong said.

"This study does a great job of saying, 'Look how serious this problem really is,'" said Dr. James Galvin, a professor of neurology and psychiatry at NYU Langone Medical Center, in New York City.

"Hospitalization is often the tipping point," he added. "The medical condition which may lead to hospitalizing may be a tipping point but clearly the hospital can be, too."

There is now a lot of focus on improving health in the home setting to avoid hospitalization and delirium, Galvin said. This includes getting the flu shot, maintaining good bladder and bowel hygiene to prevent urinary tract infections, and managing chronic pain medications that could lead to delirium.

More information

To learn more about Alzheimer's disease and delirium, visit the Alzheimer's Association.

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