Nursing homes and long-term care facilities have borne the brunt of the COVID-19 pandemic, with residents being a particularly vulnerable population due to age-related factors and the prevalence of underlying health conditions.
The Centers for Disease Control and Prevention (CDC) recognizes a number of medical conditions — including cardiovascular diseases, type 2 diabetes and obesity — for which sufficient data exists to suggest that they increase an individual’s risk of severe illness from COVID-19; however, there has been limited evidence on COVID-19 risk and outcomes in individuals with dementia, a spectrum of neurological diseases including Alzheimer’s that affects 5.8 million adults in the US over the age of 65.
Now, a large retrospective study conducted by researchers at Case Western Reserve University in Cleveland, Ohio has presented compelling evidence that individuals with dementia are, indeed, more susceptible to COVID-19 — they are two times more likely to contract the infection than patients without cognitive impairment. Those with vascular dementia showed the greatest vulnerability and were more than three times as likely to test positive for COVID-19.
Independent Association Between Dementia and COVID-19
Xtalks spoke with researchers Dr. Pamela B. Davis, the Arline H. and Curtis F. Garvin Research Professor in the Center for Clinical Investigation; and Dr. Rong Xu, Professor of Biomedical Informatics and Director, Center for AI in Drug Discovery, Case Western School of Medicine, to learn how data can inform policy on protecting adults with dementia from COVID-19, and the poor outcomes related to the disease.
“There was a pretty striking elevation in the vulnerability of people with dementia for getting the disease, and also for getting severe disease once they were infected,” Dr. Davis, who also served as Dean of Case Western’s School of Medicine for 14 years, told Xtalks. “[Dr. Xu] was able to control for the risk factors that we know are common for Alzheimer’s and COVID, like hypertension…and it seemed that even controlling for other risk factors, including the high prevalence in nursing homes, dementia was an independent risk factor for getting COVID and also for having severe disease once you got it.”
What’s more, the study found that the risk of COVID-19 among African Americans with dementia was nearly three-fold higher than that associated with their Caucasian counterparts. This is consistent with numerous reports of the disproportionate effects of COVID-19 on Black communities across the US.
Disproportionate Effect of COVID-19 on African American Communities
The infection and mortality rates in predominantly Black counties are three-times and six-times higher, respectively, compared to white-majority counties, according to results from the Johns Hopkins University and American Community Survey. These statistics highlight healthcare disparities between racial groups that have persisted for decades, if not for the better part of the past 150 years.
For the current study, the researchers used data from electronic health records (EHRs) for 61.9 million adults aged 18 years and older from the IBM Watson Health Explorys database. The article was published in Alzheimer’s & Dementia, The Journal of the Alzheimer’s Association.
Other findings from the study included trends towards worse outcomes for those with both COVID-19 and dementia. Hospitalization risk for dementia patients with COVID-19 during a six-month period was 59.26 percent, whereas hospitalization for adults without cognitive impairment was just 25.17 percent. African American patients with dementia and COVID-19 faced an even higher risk of hospitalization at 73.08 percent, versus 53.85 percent among Caucasian individuals with both conditions.
And while the COVID-19 mortality risk among the general population is 5.64 percent, patients with dementia were nearly four-times as likely to die of the infection with a mortality rate of 20.99 percent. Again, African American patients with dementia fared even worse with a mortality risk of 23.08 percent compared to the 19.23 percent for Caucasians.
Dr. Xu’s background is in using informatics to identify drugs capable of delaying the onset or altering the course of Alzheimer’s disease, a research interest supported by a grant from the National Institute of Aging (NIA). The emergence of the COVID-19 pandemic prompted Dr. Xu to investigate whether those with dementia were more likely to contract SARS-CoV-2 and suffer worse outcomes.
“People hear a lot about behavior factors, comorbidities and the age factor, but after we control for all of these, we still see a two-fold increase in risk,” said Dr. Xu.
The study authors were able to control for a number of common risk factors in their research; however, the spotty availability of non-medical data that could have a huge impact on an individual’s susceptibility to disease and access to healthcare meant that they weren’t able to identify the likely cause of this racial disparity.
“The EHRs have very limited information about socioeconomic status, so we have been trying to use insurance type,” explained Dr. Xu. “But that is not accurate because patients with Medicaid tend to go to see doctors less often.”
Compromised Blood-Brain Barrier May Explain Heightened Vulnerability to SARS-CoV-2
Dr. Xu and Dr. Davis explained that because patients with dementia, and particularly those with vascular dementia and Alzheimer’s disease, have damage to their blood-brain barrier, they may be more susceptible to viral infection. And since SARS-CoV-2 can directly affect the brain — as well as organs like the heart and lungs that are integral to maintaining brain function and health — they speculate that those with preexisting cognitive deficits as a result of dementia are at an increased risk of adverse outcomes and mortality.
“I’m surprised at the magnitude of the independent effect,” said Dr. Davis, speaking about the correlation between dementia and COVID-19 risk even after confounding variables have been controlled for. “I thought it would meld with the other risk factors known to occur in this population.”
COVID-19 Vaccine Uptake in Long-Term Care Facilities
When asked about her opinion of how the pandemic has been managed in the US in terms of protecting older adults and those living in care facilities, Dr. Davis drew on her experience as a board member for a local retirement community that spans the spectrum from independent living to nursing homes.
“Some of these communities have made enormous efforts to protect their patients,” said Dr. Davis. “They have had cases, and they’ve nearly all been in the memory care unit or in the nursing home unit. We suspect that in the memory care unit, the patients can’t remember to keep their masks on, sanitize their hands, or to stay distanced from staff, and that’s a huge risk factor.”
Both Dr. Davis and Dr. Xu agree that more doses of the COVID-19 vaccines are needed in order to better protect this vulnerable population. And ensuring that once people are vaccinated, they know to still wear their mask to protect others is critical.
“The State of Ohio prioritized vaccinations for people in congregate living facilities and I think that was smart,” said Dr. Davis. “And they prioritized vaccines for caregivers in congregate living facilities. Unfortunately, there hasn’t been good uptake of vaccines in the caregivers. There’s an excellent uptake in the patients, but for the caregivers, it’s under 40 percent. I just wish we could convince the caregivers to be more open to taking the vaccine, but I think the state did a good job in prioritization.”
But the practice of isolating these older adults to protect them from contracting SARS-CoV-2 comes at a price.
“I really worry about their mental health because they’re totally socially isolated,” said Dr. Xu.
“It’s a real conundrum: you want to protect them from the virus but their mental state is impaired by being isolated,” said Dr. Davis.
It’s a sentiment that’s shared by others in the field, like the Alzheimer’s Association’s chief science officer, Maria C. Carrillo, PhD.
“It is critical we develop and implement strategies that strike a balance between keeping people, especially long-term care residents, safe from COVID-19 but also protecting them from health-related harms associated with social isolation,” said Dr. Carrillo in a statement.
Population Data and Informatics Could Help Manage Long-Term Effects of COVID-19
Looking to the future, Dr. Davis said that findings from ongoing studies tracking the long-term effects of COVID-19 on cognitive function will be important to pay attention to, regardless of a patient’s baseline level of dementia. “Does it make you fall off a cliff, or if you’re already on the downward slide, does it accelerate that? We need to know those answers first, and then we need to try to understand why that’s happening.”
Informatics, like the methods used by Dr. Xu, will likely be important in the coming years to put the data from these large studies into perspective and identify existing drugs that may help manage emerging and worsening cases of COVID-19-related dementia.
As of January 31, 342,324 US adults aged 65 and older have died as a result of COVID-19-related causes, according to data from the CDC. This represents over 80 percent of all cases of COVID-19-related mortality in the country.
Like the State of Ohio, many others are following the guidance set forth by the Advisory Committee on Immunization Practices (ACIP) that long-term care facility residents be offered available COVID-19 vaccines first as part of the Phase 1a rollout. But COVID-19 vaccine shortages, along with lower-than-expected uptake among care home staff, are proving to be considerable challenges to the aim of protecting this vulnerable population.