Dementia Not an Independent Driver of
COVID-19 Death

Megan Brooks

April 06, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Despite concerns early in the pandemic that dementia may increase the risk for death in this patient population, new research shows it is not an independent risk factor for increased mortality.

"Our concerns for those with dementia having an increased risk of fatal COVID-19 were substantiated in general, but in further analyses, dementia itself was not an independent risk factor for mortality," study investigator James Noble, MD, Columbia University Vagelos College of Physicians and Surgeons, New York City, told Medscape Medical News.

Results also showed patients with dementia who have COVID-19 are roughly three times more likely to have delirium on arrival to the hospital but are less likely to have or report other common COVID-19 symptoms.

"Delirium and confusion are common in elderly patients with other types of infections, including pneumonia, influenza, and urinary tract infections, as well as with stroke, and our findings suggest COVID-19 causes similar symptoms in those needing hospital-level care," added Noble, associate professor of neurology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia.

The study was published online March 13 in the Journal of Alzheimer’s Disease.

A Red Flag for COVID

The researchers compared the clinical features and outcomes of 116 COVID-19 patients with previously diagnosed dementia and 415 COVID-19 patients without dementia.

All were at least 65 years old and presented to the emergency department or were hospitalized at NewYork-Presbyterian/Columbia University Irving Medical Center during the initial wave of COVID-19 that hit New York City last spring. 

On initial presentation, patients with dementia were more likely to have delirium (36.2% vs 11.6%, P < .001). 

The US Centers for Disease Control and Prevention has recognized new confusion as a warning sign in COVID-19 and findings from this cohort suggest a frequency of approximately one third of patients with dementia presenting with delirium, the researchers note.

Patients with dementia were significantly less likely to report multiple other COVID-19 symptoms including dyspnea, diarrhea, myalgias, chills, nausea/vomiting and headache.

"It's hard to say if all of these are true differences," Noble said in a news release.

"We know that, in general, people with dementia may be less likely to report some of the symptoms that we have come to recognize as typical COVID-19 symptoms because of poor awareness or they just don't remember to report these things," he added.

"Identifying a dementia-specific COVID-19 profile could help family members, caregivers, and healthcare workers recognize COVID-19 illness more promptly, which could meaningfully impact health seeking behaviors and outcomes," the researchers note.

The study also showed higher in-hospital death rates in patients with dementia (50% vs 35.4%, P = .006). However, in multivariate analysis, dementia was not independently associated with COVID-19 death.

"Instead, other factors including age, and comorbidities known to be associated with worse COVID-19 outcomes, seemed to drive these relationships," said Noble.

Not Surprising

Commenting on the findings for Medscape Medical News, Yun Freudenberg-Hua, MD, associate professor, Litwin Zucker Center for Alzheimer's Disease at the Feinstein Institutes for Medical Research in Manhasset, New York, noted, "COVID-19 is associated with a large range for neurological and neuropsychiatric symptoms ranging from loss of smell to psychosis, encephalitis, and stroke. So it's not surprising to find delirium to be common in COVID patients, especially in elderly patients.

"Generally speaking, patients with dementia are more likely to develop delirium, especially in the hospital setting. Delirium superimposed on dementia can be triggered by any infections, even those considered harmless for younger people without dementia, such as a urinary tract infection," said Freudenberg-Hua.

She also noted that there are "many overlaps between symptoms of delirium and behavioral symptoms that are typical for dementia. Distinguishing the two diagnoses in the hospital setting can be challenging, even for experienced clinicians."

Should onset of delirium prompt a COVID test? "Given the current high infection rate of COVID, definitely yes," said Freudenberg-Hua.

No specific funding or grants were received for the prior study of which this research was based on. This study was supported by a grant from the National Institute on Aging . Noble and Freudenberg-Hua have disclosed no relevant financial relationships.  

J Alz Dis. Published online March 13, 2021. Full text

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