The study by Davis et al. is important work that adds further evidence, using results from a population-based study of older individuals, that delirium, even after adjusting for age, is a risk factor for dementia.

Furthermore, in individuals with existing dementia, delirium was shown to be associated with worsening dementia severity, worsening global functional status, and higher mortality. A particular strength of this prospective cohort study is the inclusion of autopsy data in about half of the subjects both with and without a history of delirium. Unfortunately, the study was not sufficiently powered to determine if delirium is truly associated with an altered pattern of dementia pathology, although the results do suggest that delirium does not affect dementia pathology. If this is true, then the mechanisms by which delirium accelerates cognitive and functional decline and increases mortality may occur independently of dementia pathology.

Many of the findings in this study agree with the work our group has done looking at the effects of delirium on patients with...  Read more

The study by Davis et al. is important work that adds further evidence, using results from a population-based study of older individuals, that delirium, even after adjusting for age, is a risk factor for dementia.

Furthermore, in individuals with existing dementia, delirium was shown to be associated with worsening dementia severity, worsening global functional status, and higher mortality. A particular strength of this prospective cohort study is the inclusion of autopsy data in about half of the subjects both with and without a history of delirium. Unfortunately, the study was not sufficiently powered to determine if delirium is truly associated with an altered pattern of dementia pathology, although the results do suggest that delirium does not affect dementia pathology. If this is true, then the mechanisms by which delirium accelerates cognitive and functional decline and increases mortality may occur independently of dementia pathology.

Many of the findings in this study agree with the work our group has done looking at the effects of delirium on patients with Alzheimer's disease. We have also shown that there is an acceleration of cognitive decline after delirium that persists up to five years after the delirium episode, and that hospitalization and delirium result in poor outcomes—cognitive decline, mortality, and institutionalization—for patients with AD. These data all suggest that delirium, which is a preventable condition, should be handled as a genuine medical emergency, and will hopefully motivate intervention studies that would look at whether avoiding hospitalization (such as Hospital at Home) and/or delirium prevention strategies (such as the Hospital Elder Life Program) can reduce the risk of poor outcomes in patients with AD. Ultimately, if we can show that delirium prevention can delay cognitive decline and improve outcomes, this may be a far more effective strategy for maintaining cognition and functional status than the current symptomatic drug treatments that are available, and would, in general, allow us to provide better care for patients with AD.

View all comments by Tamara G. Fong