Two “easily measured” signs of health are also distinctly predictive of higher mortality, according to a study of patients hospitalized with COVID-19 published this month in the journal Influenza and Other Respiratory Viruses: respiration rate and blood-oxygen saturation.
“Initially, most patients with COVID don’t have difficulty breathing. They can have quite low oxygen saturation and still be asymptomatic,” said Dr. Nona Sotoodehnia, co-director of the Cardiovascular Health Research Unit at the University of Washington School of Medicine.
“If patients follow the current guidance, because they may not get short of breath until their blood oxygen is quite low, then we are missing a chance to intervene early with life-saving treatment,” said Sotoodehnia, who is also a co-lead author of the paper.
The researchers examined the cases of 1,095 patients aged 18 and older admitted with COVID-19 to University of Washington Medicine hospitals in Seattle or to Rush University Medical Center in Chicago from March 1 to June 8, 2020; 197 of those patients died in the hospital.
The Centers of Disease Control and Prevention list mild to severe symptoms that could appear two to 14 days after exposure to the virus. They include shortness of breath or difficulty breathing, fever or chills, cough, fatigue, muscle or body aches, headache, and new loss of taste or smell.
The CDC tells people to seek emergency medical attention if they have “trouble breathing, persistent pain or pressure in the chest, new confusion, inability to wake or stay awake, or pale, gray, or blue-colored skin, lips, or nail beds, depending on skin tone.”
CDC guidance and context
The authors of the new paper argue that the CDC guidance lacks suitable context.
“These findings apply to the lived experience of the majority of patients with COVID-19: being at home, feeling anxious, wondering how to know whether their illness will progress, and wondering when it makes sense to go to the hospital,” said study co-author Dr. Neal Chatterjee, a cardiologist and cardiac electrophysiologist at the University of Washington School of Medicine.
Patients often had hypoxemia — low blood-oxygen saturation, measured at 91% or below in this study — or tachypnea, which is fast, shallow breathing, measured at 23 breaths per minute in this study. But few reported shortness of breath or coughing.
Hypoxemic patients had a mortality risk 1.8 to 4 times greater than those admitted with normal blood oxygen. Similarly, those with tachypnea had a mortality risk 1.9 to 3.2 times greater. Other clinical signs, such as temperature, heart rate and blood pressure, were not associated with mortality.
Sotoodehnia recommended that people with positive COVID-19 test results — especially people who are at higher risk of more severe illness, such as those who have diabetes, older patients or those who are obese — obtain a pulse oximeter and monitor for blood oxygen below 92%.
The government continues the rollout of vaccines from Johnson & Johnson JNJ, -0.10%, Pfizer-BioNTech PFE, +0.46% BNTX, -1.86% and Moderna MRNA, +1.89%. As of Monday, 39.2% of the total U.S. population had been fully vaccinated against COVID-19 and more than 49.2% had received at least one dose.