Dementia and COVID: What Families and Physicians Should Know

In people with dementia, delirium during COVID-19 is more common but deaths from COVID-19 are not disproportionately higher, finds new study

New York, NY, USA – 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, has been published online 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 to 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 a ‘warning sign’ of COVID-19, and this study suggests this was especially common in people with dementia hospitalized with COVID-19,” Noble says. “This is important for caregivers and health care providers of homebound Alzheimer’s patients who have not been vaccinated yet.”


Full open access study: “Clinical Features and Outcomes of Patients with Dementia Compared to an Aging Cohort Hospitalized During the Initial New York City COVID Wave” by Amro A. Harb, RuiJun Chen, Herbert S. Chase, Karthik Natarajan, and James M. Noble (DOI: 10.3233/JAD-210050), published online in the Journal of Alzheimer’s Disease ahead of the publication of Volume 81, Issue 2 (2021). The article is freely available at:

James Noble, MD, MS, also has an appointment at the Gertrude H. Sergievsky Center in the Department of Neurology at Columbia University Vagelos College of Physicians and Surgeons.

Other authors (all from Columbia) are RuiJun Chen, Herbert Chase, and Karthik Nataranjan.

The study was supported by an NIH training grant (T-35AG044303). The authors report no financial or other conflicts of interest.

For further information, get in touch with the media contact Helen Garey, Columbia University Irving Medical Center (

About Columbia University Irving Medical Center
Columbia University Irving Medical Center provides international leadership in basic, preclinical, and clinical research; medical and health sciences education; and patient care. The medical center trains future leaders and includes the dedicated work of many physicians, scientists, public health professionals, dentists, and nurses at the Vagelos College of Physicians and Surgeons, the Mailman School of Public Health, the College of Dental Medicine, the School of Nursing, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions. Columbia University Irving Medical Center is home to the largest medical research enterprise in New York City and State and one of the largest faculty medical practices in the Northeast.

About the Journal of Alzheimer's Disease
Now in its 24th year of publication, the Journal of Alzheimer's Disease (JAD) is an international multidisciplinary journal to facilitate progress in understanding the etiology, pathogenesis, epidemiology, genetics, behavior, treatment, and psychology of Alzheimer's disease. The journal publishes research reports, reviews, short communications, book reviews, and letters-to-the-editor. Groundbreaking research that has appeared in the journal includes novel therapeutic targets, mechanisms of disease, and clinical trial outcomes. JAD has a Journal Impact Factor of 3.909 according to Journal Citation Reports (Clarivate, 2020). JAD is published by IOS Press.