Study Finds Dementia Patients Are Twice as Likely to Get COVID-19—Here’s What You Need to Know
They're also more likely to experience severe disease resulting in hospitalization or death.
Since beginning of the COVID-19 pandemic, we've been told that those with preexisting conditions—cancer, diabetes, pulmonary diseases—were at a greater risk of severe illness from the virus. Now, another might be added to that list: dementia.
The news comes from a study published February 9 in Alzheimer's & Dementia, the journal of the Alzheimer's Association, and found that people with dementia are at a greater risk of contracting COVID-19 and experiencing severe disease than those without.
For the study, researchers at Case Western Reserve University analyzed almost 61.9 million electronic health records of people age 18 and older in the US, from February 1 through August 21, 2020. The data came from 360 hospitals and 317,000 health care providers across all 50 states, representing a fifth of the US population.
Old age, living in a nursing home, and having conditions like asthma, diabetes, cardiovascular disease, and obesity, are known risk factors for COVID-19, per the study. But even after adjusting for those factors, the researchers found that Americans with dementia were still twice as likely to have been infected with COVID-19 as those who don't have dementia. And regarding severe disease for COVID-19 patients with dementia, researchers found that they were 2.2 times more likely to have been hospitalized within the first six months of the pandemic, and 4.4 times more likely to have died from the disease.
There has been speculation about whether people with dementia are more prone to infection and serious harm from COVID-19 throughout the pandemic, so the study findings didn't come as a surprise, senior author Rong Xu, PhD, tells Health.
The authors subdivided patients by the type of dementia listed in their records, and found that those with vascular dementia had a greater risk for infection than people designated as having Alzheimer's disease or other types. This is where it's important to understand that dementia is a general term for a decline in mental ability—including memory, reasoning, and other thinking skills—severe enough to interfere with daily life. While Alzheimer's, the most common cause of dementia, is a specific disease, dementia is not, says the Alzheimer's Association.
Vascular dementia (VaD) is caused by conditions that damage blood vessels and reduce or block blood flow to the brain, for instance when a stroke blocks an artery, or high blood pressure damages blood vessels over time, per the Weill Institute for Neurosciences. The study authors note that there is significant overlap between types of dementia, and that many patients have both VaD pathology and Alzheimer's pathology, which may not be designated in electronic records.
The researchers also studied racial disparities, and found that Black people with COVID-19 and dementia were three times more likely to be hospitalized than white people who had both diseases. While they didn't find a significant difference in the mortality rate for Black and white COVID-19 patients with dementia, they acknowledged that the number of deaths analyzed (170) might simply be too small to reach a substantial conclusion.
It's undeniable that racial inequality and white privilege affects health and health care in a major way—an ever-increasing body of research shows that Black, Indigenous, and people of color in the US experience more illness, worse outcomes, and premature death, compared with white people. It's a complex issue, with many factors.
"We think that social-economic and behavioral factors may have played important roles here," says Xu, a professor of biomedical informatics at Case Western. "However, we could not test this due to limited social-economic and behavioral information captured in patients' electronic health records."
The fact that the data only reflects people who have connected with the health care system, and therefore doesn't include the patients who find it more difficult to access health care due to social isolation or financial difficulties, means there may be an even greater COVID-19 infection risk for those with dementia.
"This is a very interesting study," Joshua Chodosh, MD, the Michael L. Freedman Professor of Geriatric Research and director of Geriatric Medicine and Palliative Care at NYU Grossman School of Medicine, tells Health. Dr. Chodosh points out that there may be a bias in detection compared to people who stay home and become ill and/or die with the disease, because more people with dementia are likely to use hospitals. "Those at home do not get detected as often," he says.
However, Dr. Chodosh also notes that if someone has dementia, wearing a mask and complying with social distancing will be far more difficult. "Moreover, if your disability requires a caregiver in close contact, the risks and repeated exposures will likely increase the risk of disease and of disease severity," he adds.
"If there is a need for ADL (activities of daily living) assistance due to dementia, that increases the need for close contact with others and the risk of infection," Dr. Chodosh says. "This would be true for needed help with bathing, dressing, using the bathroom, and eating, for example."
As Dr. Chodosh explains, with dementia comes greater difficulty with behaviors, making the introduction of new behaviors (for instance, to reduce the risk of COVID-19 infection) very challenging. "There will also be greater likelihood for misinterpreting why someone else is wearing a mask and greater challenge for recognition of others who may even be family members if masks are in place—an impediment to mask wearing," he says. This in itself might exacerbate behavioral issues.
Xu hopes the study findings will encourage wide adoption of vaccination and protective measures, such as mask wearing, for care-givers and patients with dementia.
The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.
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