Nov. 19 (UPI) -- More than 1 in 4 older adults with COVID-19 first experience delirium -- a state of confusion or disorientation -- before other symptoms of the virus appear, according to a study published Thursday by JAMA Network Open.
Delirium was the "primary" symptom of 16% of older patients in the study, who were all age 68 to 86, the data showed.
In addition, 37% of the patients never developed the "typical" symptoms of infection, including fever and shortness of breath, the researchers said.
"Older adults...sometimes present atypically, meaning they may not have the symptoms that we usually associate with COVID-19, such as cough, fever, body aches or breathing symptoms," study co-author Dr. Maura Kennedy told UPI.
"Additionally, older adults might have non-specific symptoms, including confusion or delirium, feeling weak or feeling dizzy," said Kennedy, an attending physician in the emergency department at Massachusetts General Hospital in Boston.
Many severely ill older adults -- with or without COVID-19 -- experience delirium, which is described as an acute state of confusion, with an altered level of consciousness, disorientation, inattention and other cognitive disturbances.
Still, roughly two-thirds of delirium cases go undetected by emergency room personnel, and sufferers are at increased risk for prolonged hospitalization and death, the researchers said.
"The symptoms of delirium can be varied -- sometimes people suddenly don't recognize family members, while others may be very sleepy and may sleep through meals and others may became agitated or even hallucinate," Kennedy said.
For this study, the researchers reported on 817 older adults who were admitted to emergency rooms for possible COVID-19 infection at seven hospitals across the United States on or after March 13.
Infection was confirmed in all 817 patients, and 28% had delirium when they arrived at the hospital, the researchers said.
Delirium sufferers were 67% more likely to require intensive-care unit treatment for COVID-19 and 24% more likely to die from the disease than others.
Older patients with a vision impairment had a 98% higher risk for delirium from COVID-19.
In addition, those with Parkinson's disease were 88% more likely to suffer from delirium, while those 75 and older were at 51% higher risk for the symptom, compared to younger patients.
Patients who had previously suffered a stroke had a 47% higher risk for COVID-19-related delirium, while those living in nursing homes or assisted living facilities had 23% higher risk.
Nursing homes across the United States reported more than 10,000 new cases of the virus during the week ending Nov. 1, according to a report from the American Health Care Association and National Center for Assisted Living. That would represent a 40% rise since the beginning of October.
The new study highlights the need for staff across all care settings, including long-term and assisted-living facilities, emergency departments and hospitals, to recognize delirium and test for COVID-19 "if someone is newly delirious," Kennedy said.
"Early recognition of delirium is important to prevent disease transmission within healthcare and residential facilities," she said.