For the elderly, a stay in the intensive care unit (ICU) can be stressful and may be linked to dementia. A recent study found that some ICU experiences may raise the risk of dementia.
The study tracked elderly people for three years after a stay in the ICU. People who had certain types of infection, short-term mental problems or received dialysis while in the ICU were more likely to develop dementia.
This link may help doctors and patients to know when they need to watch for changes in memory more closely.
The study, led by Carmen Guerra, MPH, with senior scientist Hannah Wunsch, MD, of the College of Physicians & Surgeons at Columbia University, followed people’s records for three years after an ICU stay. There were 25,368 people on Medicare who were in the study. Medicare is only available to people over age 65. None of them had a diagnosis of dementia at start of the study.
The researchers used their patient charts to find out why they were in the ICU and what treatments they had while they were there. During the study, 4,519 people developed dementia - or 17.8 percent. It was estimated in 2007 that 13.9 percent of Americans over age 71 had dementia.
The researchers looked to see if developing dementia was linked to any ICU experiences. They found that people who had certain types of experiences were more likely to develop dementia in the years after their stay in ICU.
People who had an infection or severe sepsis, a blood infection, were more likely to develop dementia. Also, receiving dialysis while in the ICU, but not otherwise having kidney failure, also made it more likely for people to develop dementia.
People who were in the ICU for brain damage or who had short-term mental problems while in the ICU were also more likely to develop dementia.
The authors concluded that, “These findings suggest that certain diseases and events associated with a critical illness may increase the risk of dementia, or ‘unmask’ previously undiagnosed dementia.”
This study cannot say that these ICU experiences caused dementia, however. Some unknown factors that contribute to a stay in the ICU may also contribute to the development of dementia.
The researchers did not test cognitive skills at the beginning of the study. So it is possible that some people had early signs of dementia that had not been diagnosed. The experiences in the ICU may have just brought cognitive difficulties to light.
This study was published December 17 in Critical Care. The authors report no competing interests.
The study was funded by grants from the Foundation for Anesthesia Education and Research, the National Institute On Aging, the National Center for Research Resources and the National Center for Advancing Translational Sciences.