COVID-19 patients with dementia have higher risk for complications, mortality

Reviewed by Emily Henderson, B.Sc.Mar 31 2021

Early in the pandemic, neurologists expressed concern that COVID-19 patients with dementia may be at higher risk for complications and mortality.

But those fears have not been realized, according to a new study of patients who were hospitalized with COVID-19 during the first wave of the pandemic in New York City. The study, led by James Noble, MD, MS, associate professor of neurology at Columbia University Vagelos College of Physicians and Surgeons and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain, and Amro Harb, a Vagelos medical student, was published this month in the Journal of Alzheimer's Disease.

Though the study found a greater proportion of patients with dementia had died, "other factors, including age and comorbidities, were really the driving factors and not dementia itself," Noble says.

One unmistakable difference among patients, however, was the greater incidence of delirium in those with dementia.

"Early in the pandemic, we received many calls from caregivers about the sudden development of confusion and delirium in our dementia patients, even in those with only mild COVID symptoms," Noble says. "Delirium and confusion are common in elderly patients with other types of infections, including pneumonia, influenza, and urinary tract infections, and we realized delirium might be an unrecognized symptom of COVID-19 in this population."

That observation was reflected in the data from the hospitalized patients, where delirium was found in more than 36% of patients with dementia versus less than 12% of patients without dementia.

The dementia patients with COVID-19 were also less likely to report subjective symptoms such as shortness of breath, muscle aches, chills, nausea, or headaches compared with patients without dementia.

"It's hard to say if all of these are true differences," Noble says. "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."

Regardless of the reason behind the differences, Noble says the study suggests we may need to look beyond conventional symptoms associated with COVID-19 in this population and consider confusion and delirium as possible common signs of infection.

The CDC has recognized new confusion is a 'warning sign' of COVID-19, and this study suggests this symptom was especially common in people with dementia hospitalized with COVID-19. This is important for caregivers and health care providers of homebound Alzheimer's patients who have not been vaccinated yet."

James Noble, MD, MS, Associate Professor of Neurology, Columbia University Vagelos College of Physicians and Surgeons