Hospital study finds connection between dementia, delirium and declining health

More than half of all patients with pre-existing dementia will experience delirium while hospitalized. Failing to detect and treat their delirium early leads to a faster decline of both their physical and mental health, according to health researchers.

"This study is important, as delirium is often overlooked and minimized in the hospital setting, especially in persons with dementia," said Donna M. Fick, Distinguished Professor of Nursing at Penn State and principal investigator for this study. "And it illustrates that delirium is deadly, costly and impacts patient functioning."

The researchers followed 139 hospitalized adults, ages 65 and older, with dementia and found that the patients who developed delirium had a 25 percent chance of dying within 30 days, as reported in the current issue of the Journal of Hospital Medicine.

Dementia is an irreversible, progressive condition that affects cognitive and physical function. Symptoms usually occur over months to years and can include memory loss, inability to solve simple problems, difficulties with language and thinking, personality and behavior changes and other mental problems.

Delirium, on the other hand, is a reversible cognitive condition that comes on quickly and if caught and treated early can be resolved. Many of the symptoms of delirium may appear similar to dementia, but signs such as marked inattention and sleepiness or hyperactivity can help differentiate delirium from dementia.

Fick and colleagues focused on this combination of disorders, known as delirium superimposed on dementia (DSD), in this study. The researchers found a 32 percent incidence of new delirium in the hospitalized patients with dementia. These patients stayed in the hospital about four days longer than patients without delirium, and also had a reduced level of physical and mental ability when they left the hospital and at follow-up visits one month later. Additionally, patients with DSD were more likely to have died a month after their hospital stay.

Patients with Alzheimer's disease who suffered episodes of delirium while hospitalized had a sharply increased rate of mental decline for up to five years after being hospitalized compared to those who did not have any such episodes, according to a study by researchers at The Institute for Aging Research at Hebrew SeniorLife, an affiliate of Harvard Medical School.

The paper, published today in the Archives of Internal Medicine, noted that delirium - an acute decline in cognitive status, particularly attention and executive function, that typically lasts for a day or several days - is highly prevalent among Alzheimer's patients who are hospitalized.

"Delirium developed in more than half of the patients we studied," said Alden L. Gross, PhD, MHS, a postdoctoral researcher at the Institute and lead author of the study, the first to examine the significance of the prevalence of delirium over such an extended period of time.