March 9, 2021
People with dementia are twice as likely to get Covid-19, the disease caused by the novel coronavirus, and four times more likely to die of the disease than the general population. Those are the findings from a huge analysis of patients during the first six months of the coronavirus pandemic. The results underscore the particular hazards of Covid-19 for people with dementia, of which Alzheimer’s disease is the most common form.
For the study, researchers at Case Western Reserve University analyzed electronic health records from 61.9 million American adults — or about 20 percent of the U.S. population. The researchers found that people with dementia were much more likely to contract coronavirus, and to get seriously ill or die from it, than those without dementia.
Blacks with dementia were at particularly high risk. They were nearly three times more likely to become infected with coronavirus than whites with dementia.
“Our results emphasize how important it is to protect those with dementia from acquiring SARS-CoV-2, for they are at higher risk for severe disease than those without dementia,” said study author Pamela Davis, dean emerita of the Case Western Reserve School of Medicine. The findings were published in the journal Alzheimer’s and Dementia.
The researchers suggested various reasons why someone with Alzheimer’s disease or other forms of dementia might be more susceptible to Covid-19. People with Alzheimer’s disease would have a harder time maintaining appropriate social distancing measures (keeping at least six feet from others); be less attentive to wearing a mask properly and keeping a mask on; and be less likely to be fastidious about washing their hands often or minimizing contacts with their environment in public places (door handles, bathrooms, bus and subway handles, etc). People with dementia are also more likely to live in nursing homes, which were hotbeds of Covid activity in some states.
Risk factors for dementia, including being overweight, or having high blood pressure or diabetes, are also risk factors for worse outcomes for those who develop Covid. The researchers considered and corrected for many of these factors; still, the risk of getting seriously ill, and dying, from Covid remained higher in those with dementia.
The researchers speculated that there may be physiological factors, such as impairments to the blood-brain barrier, that make people with dementia especially vulnerable to coronavirus, though more research is needed. It is also to be expected that someone with dementia will be more easily overwhelmed by Covid symptoms and treatments, and might therefore require hospitalization sooner than their peers without dementia.
Overall, the risk that an American man or woman with Covid would require hospitalization during the first six months of the pandemic was about 25 percent. But among those with dementia, the hospitalization rate for Covid was nearly 60 percent. Among African Americans with dementia and Covid, the hospitalization rate was 73 percent.
The overall mortality rate for Covid was 5.64 percent. But among those with Covid who had dementia, nearly 21 percent died.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: QuanQiu Wang MS; Pamela B. Davis MD,PhD; Mark E Gurney PhD; Rong Xu PhD: “COVID-19 and dementia: analyses of risk, disparity and outcomes from electronic health records in the US.” Alzheimer’s and Dementia, February 9, 2021