March 21st, 2012
05:04 PM ET
People 65 years of age and older experience cognitive decline an average of 2.4 times faster if they have been hospitalized, compared to people of the same age who haven't, according to a new study.
For the study, published in Neurology, Robert S. Wilson, PhD. and colleagues reviewed the cognitive decline of more than 1,800 patients aged 65 and older who lived in Chicago. The patients were given a baseline cognitive test and then followed for an average of nine years with the same cognitive test repeated at least three times at intervals of three years.
They found that the natural cognitive decline people begin to experience as they age was sped up after a person had been hospitalized, regardless of the reason or how long the hospitalization lasted.
"We were expecting that there might be some effect but I didn't expect it to be this big, this broad," says Wilson, a professor of neurological sciences and behavioral sciences at Rush University Medical Center.
"[Their decline] had seemingly little to do with the illness that put them there in the first place. It's a very striking finding and somewhat worrisome."
Wilson points out that there is a degree of variability to the deterioration some patients may experience after being in the hospital, ranging from some individuals not seeing any change in their cognitive abilities to others declining rapidly.
"But as a population, they're doing a lot worse than they were before they went in to the hospital," says Wilson.
Why the decline varies from person to person or happens at all is still unknown. Although researchers and health care professionals have heard anecdotal evidence of this phenomenon for several years, no study has been able to identify the mechanism(s) behind it.
"That's the million dollar question," says Dr. Marie Bernard, the Deputy Director of the National Institute of Aging, who was not affiliated with the study.
"We know that older individuals in the hospital are at greater risk for developing delirium and we know that theoretically, delirium is a temporary phenomenon but reasearch shows it can last for several months. If that... leads to longer term change in cognitive abilities, we don't know."
Wilson and Bernard believe caregivers, family, and friends of people 65 and older should be aware that hospitalizations may cause a lapse in an older patient's cognitive abilities. There is no research to show definitively what steps could be taken to avoid that but Bernard believes that a close relationship with the patient's primary care doctor could help.
"It would seem reasonable that if you could avoid hospitalization, you could avoid any cognitive decline (from hospitalization)," says Bernard.
"When you see the development of new symptoms or causes for concern, contact [the patient's] primary care provider because if you're working closely with [them], you can avoid hospitalization."
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