A study published today in JAMA Network Open shows that 28% of older COVID-19 patients at seven US emergency departments (EDs) had delirium, putting them at higher risk of an intensive care unit (ICU) stay and death.
A research team led by Massachusetts General Hospital scientists found that, of 817 COVID-19 patients 65 and older arriving at EDs, 226 (28%) had delirium, which was the sixth most common of all signs and symptoms. Delirium was a primary symptom in 37 (16%) of patients with delirium. Eighty-four patients with delirium (37%) had no typical COVID-19 symptoms, such as fever or shortness of breath. (Older adults are less likely than younger people to respond to infection with a fever.)
Delirium, which involves confusion, impaired consciousness, disorientation, lack of attention, agitation, and other cognitive problems, affects mainly older people, although it's estimated to remain undiagnosed in two thirds of patients, the researchers said. In older patients with non-coronavirus infections, delirium may be the first or only sign of illness.
Advanced age, nursing home residency, underlying illnesses
Patients most likely to have delirium were older than 75 years (adjusted risk ratio [aRR], 1.51), lived in a nursing home or assisted living facility (aRR, 1.23), had previously used psychoactive medications such as antidepressants or sleep medications (aRR, 1.42), and had impaired vision (aRR, 1.98), hearing problems (aRR, 1.10), or a history of stroke (aRR, 1.47) or Parkinson's disease (aRR, 1.88). Those with 4 or more of 14 common underlying diseases were at 1.58 times the risk for delirium.
Of all patients with delirium, 112 (50%) visited the ED within 2 days of symptom onset, and 213 (94%) were admitted to the hospital. Delirium was linked to hospitalization (aRR, 1.06), ICU stays (aRR, 1.67), release to a rehabilitation facility (aRR, 1.55), and death (aRR, 1.24).
Mean patient age was 77.7 years, 26% lived in a nursing home, 30% had been previously diagnosed as having cognitive impairment or dementia, 30% had previously had a stroke, 47% were men, 62% were white, 27% were black, and 7% were Hispanic or Latino.
Call to include delirium in CDC guidance
The authors noted that although people older than 65 years make up only 16% of the US population, they have accounted for more than 80% of US COVID-19 deaths. They said that the rate of delirium in their study was much higher than that the 7% to 20% usually reported in studies in the ED setting before COVID-19, even though the risk factors for delirium are comparable to those reported in ED and hospitalized patients before the pandemic.
According to the researchers, the patients in their study may have sought emergency care later in the course of COVID-19 because family members or healthcare providers didn't recognize delirium as an important symptom or because of delays in evaluation stemming from fear of infection or problems accessing care.
"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," the authors wrote. "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."
The researchers said that future research should focus on the preventable nature of delirium in COVID-19 and the efficacy of tested intervention strategies such as the Hospital Elder Life Program or the ABCDEF bundle to curb the severity of delirium, shorten its duration, and reduce the occurrence of related complications.
And because current Centers for Disease Control and Prevention (CDC) guidance includes new-onset confusion as only a warning sign, not a symptom, of COVID-19, the authors called for the agency to immediately revise its guidance to include delirium as an importance coronavirus symptom.
"Many centers use the CDC guidance to prioritize screening, testing, and evaluation of presenting patients," they said. "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."