People with dementia had a significantly higher risk of contracting the coronavirus, and they were much more likely to be hospitalized and die from it, than people without dementia, a new study of millions of cases found. medical in the United States.
Their risk could not be fully explained by characteristics common to people with dementia that are known risk factors for Covid-19: old age, living in a nursing home, and conditions such as obesity, l asthma, diabetes and cardiovascular disease. After researchers adjusted for these factors, Americans with dementia were still twice as likely to have contracted Covid-19 at the end of last summer.
“It’s pretty compelling to suggest that there is something about dementia that makes you more vulnerable,” said Dr. Kristine Yaffe, professor of neurology and psychiatry at the University of California at San Francisco, who doesn’t did not participate in the study.
The study found that black people with dementia were almost three times more likely than white people with dementia to be infected with the virus, a finding that experts say most likely reflected the fact that people of color have generally suffered disproportionate damage during the pandemic.
“This study highlights the need to protect patients with dementia, especially those who are black,” the authors wrote.
Maria Carrillo, chief scientist of the Alzheimer’s Association, which heads the journal that published the study, Alzheimer’s and Dementia, said in an interview: “One of the things that comes out of this Covid situation is that we should highlight these disparities. . “
The study was conducted by researchers at Case Western Reserve University who analyzed the electronic health records of 61.9 million people aged 18 and older in the United States from February 1 to August 21, 2020. data, collected by IBM Watson Health Explorys, came from 360 hospitals and 317,000 health care providers in all 50 states and represented one-fifth of the US population, the authors said.
Rong Xu, professor of biomedical informatics at Case Western and lead author of the study, said there had been speculation about whether people with dementia were more prone to infections and damage from Covid-19.
“We thought, ‘We have the data, we can just test this hypothesis,’ Dr Xu said.
The researchers found that out of 15,770 patients with Covid-19 in the records analyzed, 810 of them also had dementia. When researchers adjusted for general demographic factors – age, sex, and race – they found that people with dementia were more than three times more likely to contract Covid-19. When they adjusted for Covid-specific risk factors like nursing home residency and underlying physical conditions, the gap narrowed somewhat, but people with dementia were still twice as likely to ‘be infected.
Experts and study authors said the reasons for this vulnerability could include cognitive and physiological factors.
“People with dementia are more dependent on those around them to ensure safety, to remember to wear a mask, to keep people away through social distancing,” said Dr. Kenneth Langa, professor of medicine at the University of Michigan , who did not participate in the study. “There’s the cognitive impairment and the fact that they’re more socially at risk,” he says.
Dr Yaffe said there could also be an “element of frailty” in people with dementia, including a lack of mobility and muscle tone, which could affect their resilience to infections.
Dr Carrillo noted that the coronavirus infection was associated with an inflammatory response that has been shown to affect blood vessels and other aspects of the circulatory system. Many people with dementia already have vascular disorders, which can be made worse or amplified by Covid-19.
Indeed, the study authors subdivided patients according to the type of dementia listed in the electronic records and found that people designated as having vascular dementia had a greater risk of infection than those designated as having vascular dementia. Alzheimer’s disease or other types.
But Dr Langa and Dr Yaffe warned that there was a significant overlap between types of dementia. Many patients have both Alzheimer’s disease and vascular disease, they said, and physicians who are not specialists may not distinguish the subtypes when providing codes for electronic records.
In examining the risk of hospitalization and death for patients with Covid dementia, the researchers did not adjust demographics such as age or whether they lived in nursing homes or had under-developed medical conditions. underlying. They found that dementia patients with Covid were 2.6 times more likely to have been hospitalized in the first six months of the pandemic than those without dementia. They were 4.4 times more likely to die.
Blacks with Covid-19 and dementia were significantly more likely to be hospitalized than whites with both diseases. The authors did not find a significant difference in the death rate of black-and-white coronavirus patients with dementia, although they wrote that the number of deaths analyzed, 170, may be too small to provide a conclusion. solid about it.
Experts noted that one of the limitations of the study was that researchers did not have access to socio-economic information, which could lead to a better understanding of patients’ risk factors.
Dr Langa also noted that the data only reflected people who interacted with the health system, so it did not include “more isolated and poorer patients who have a harder time getting to homes. doctors”.
Therefore, he said, the study could be “an underestimate of the higher risk of Covid infection for people with dementia.”