Study suggests delirium may be present without other typical Covid-19 symptoms

Delirium is common among elderly patients presenting to Emergency Departments, but it may also be a presenting symptom of Covid-19 infection with or without more common symptoms, and should be on clinicians checklists for the virus, according to a new study published in JAMA Network Open.

The multicenter retrospective cohort study found that of 817 older patients diagnosed with Covid-19, 28% of them had delirium when they presented at the Emergency Department and it was the sixth most common sign of Covid-19, Maura Kennedy, MD, MPH, from Department of Emergency Medicine, Massachusetts General Hospital, Boston, and colleagues, explained.

“Among patients with delirium, delirium was the main presenting symptom in 16%,” Kennedy and colleagues wrote. “Importantly, 37% of patients with delirium did not have typical Covid-19 symptoms of fever or shortness of breath. Factors associated with risk of delirium included older age, prior psychoactive medication use, assisted living or skilled nursing facility residence, vision or hearing impairment, stroke, and Parkinson’s disease.”

Kennedy and colleagues also noted that the Covid-19 patients who had delirium upon presentation had an “increased risk for poor hospital outcomes, including ICU stay, discharge to a rehabilitation facility, and death.”

Atlhough delirium is a common morbidity in the elderly, Kennedy and colleagues noted that in their study that there was a higher than usual incidence of delirium compared with ED studies prior to the Covid-19. In those pre-pandemic studies the range of delirium was 7% – 20%, “although the factors associated with risk of delirium are similar to those identified in ED and inpatient research before Covid-19,” they wrote.

That said, Kennedy et al’s study appears to be adding to the growing body of evidence that show “this high occurrence of delirium and other neuropsychiatric manifestations with Covid-19 with previously reported rates of 22% to 33% among hospitalized patients.”

The researchers conducted their study at seven U.S. sites, and included consecutive older adults with Covid-19 who presented at the ED on or after March 13, 2020. Covid-19 was diagnosed by either positive nasal swab or classic radiological findings (99% and 1% respectively). Delirium was the primary outcome measure of the study.

Most of the 817 patients were white (493, 62%), 27% were Black), and 7% were Hispanic or Latinx. Less than half of the study population was male, and the mean age of all the patients was 77.7 years (SD 8.2 years).

“Factors associated with delirium were age older than 75 years (adjusted relative risk [aRR], 1.51; 95%CI, 1.17-1.95), living in a nursing home or assisted living (aRR, 1.23; 95%CI, 0.98-1.55), prior use of psychoactive medication (aRR, 1.42; 95% CI, 1.11-1.81), vision impairment (aRR, 1.98; 95%CI, 1.54-2.54), hearing impairment (aRR, 1.10; 95%CI 0.78-1.55), stroke (aRR, 1.47; 95%CI, 1.15-1.88), and Parkinson disease (aRR, 1.88; 95%CI, 1.30-2.58),” Kennedy and colleagues wrote.

Delirium was associated with intensive care unit stay (aRR, 1.67; 95%CI, 1.30-2.15) and death (aRR, 1.24; 95%CI, 1.00-1.55).”

The study authors noted that fever, cough, shortness of breath, and difficulty breathing are the typical Covid-19 symptoms. “Fever has been reported to be present in 80% of patients with Covid-19, but it was present in only 56% of our patients,” they wrote. “The absence of typical symptoms or signs is potentially attributable to physiological changes associated with aging. Older adults have a lower basal temperature and an impaired ability to mount a febrile response in the setting of acute infection.”

In light of the lack of these typical Covid-19 symptoms, Kennedy and colleagues wrote: “Our study demonstrates that clinicians must include Covid-19 in the differential diagnosis of delirium among older adults, regardless of whether they have other symptoms of Covid-19 infection. This is important to avoid missing diagnoses altogether and to better identify severe cases of Covid-19 at high risk for poor outcomes and death.”

They also wrote that the study’s data “strongly support an immediate revision in CDC guidance on symptom profiles for Covid-19 to include delirium as an important Covid-19–related symptom. Current CDC guidance lists new confusion as an emergency warning sign only, not as a presenting symptom in COVID-19. Many centers use the CDC guidance to prioritize screening, testing, and evaluation of presenting patients. By continuing to exclude delirium as a known presenting symptom of Covid-19, many cases will be missed or diagnoses delayed, as is already happening on a wide scale, particularly in older adults.”

The study authors cited several limitations of the study, including the fact that they believe that the percentage of delirium observed in the study in an underestimate of the true rate, because of reliance on medical record documentation. The researchers also noted that the use of medical imaging rather than PCR testing in a small percentage of cases could have led to misdiagnosis.

  1. Delirium may be a presenting symptom for Covid-19 in elderly patients presenting to the Emergency department.
  2. In this study, the researchers noted that the Covid-19 patients who had delirium upon presentation had an “increased risk for poor hospital outcomes, including ICU stay, discharge to a rehabilitation facility, and death.”

Candace Hoffmann, Managing Editor, BreakingMED ™

This study was supported in part by a grant from the National Institute on Aging and from the MSTP Training Program at the University of Massachusetts Medical School.

Kennedy reported no relevant relationships.


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