The study, which represents the largest cohort of hospitalized patients with COVID-19 in the United States thus far, confirmed that the highest-risk groups are older, male, and those with preexisting hypertension, diabetes, or obesity.
Mortality rates are difficult to compare between studies, emphasizes corresponding author Karina W. Davidson, PhD. Health care systems and resources can affect outcomes as well as patient demographics and the prevalence of comorbidities. In addition, “the speed with which people present with symptoms and where they are in the course of disease” differ between patient series, said Dr. Davidson, professor and senior vice president at the Feinstein Institutes for Medical Research and senior vice president of research, Northwell Health, Manhasset, N.Y.
“But given all of those, we know that our study represents a fairly large sample of consecutive patients. This is what the mortality rate looks like among those requiring hospitalization at the early stage of the pandemic,” Dr. Davidson said.
The large patient sample reflects the diversity of the city and its environs. “It’s a large representative sample of very diverse patients ranging in age from zero (under a year) to 107, from all walks of life and socioeconomic levels,” Dr. Davidson continued. Eight of the 12 participating N.Y.C.–area hospitals are on Long Island, one each in Manhattan and Staten Island, and two in Queens.
For the study, first author Safiya Richardson, MD, MPH, and colleagues in the Northwell COVID-19 Research Consortium analyzed EHRs of 5,700 patients hospitalized with confirmed COVID-19 during March 1, 2020–April 4, 2020.
Overall, 1,151 (20.2%) of the 5,700 patients required mechanical ventilation. As of April 4, 831 (72.2%) of these patients remained in the hospital, 38 (3.3%) were discharged, and 282 (24.5%) had died.
When the authors restricted their analysis to the 2,634 patients whose outcomes (discharge or death) were known at the end of the study, 373 (14.2%) had been treated in the intensive care unit, 320 (12.2%) received invasive mechanical ventilation, 81 (3.2%) received dialysis, and 553 (21%) died.
As seen in other COVID-19 studies, increasing age was associated with a higher risk of death. Of patients receiving mechanical ventilation and whose outcomes (discharge or death) were known, 88.1% died. When stratified by age, the mortality rates for ventilated patients were 76.4% for those aged 18-65 years and 97.2% for those older than 65 years.
Among those who did not require mechanical ventilation and whose outcomes (discharge or death) were known, 19.8% of patients aged 18-65 years died, as did 26.6% of those older than 65 years. No patient under 18 years died during the study period.
“There can be risks with mechanical ventilation, like the development of ventilator-associated pneumonia (VAP), which occurs in 10%-25% of ventilated patients and tends to occur within 5 days. The authors didn’t report data on VAP, but it seems that the mortality for ventilated patients would most likely be attributable to disease severity rather than the ventilation itself,” said Cindy Prins, PhD, director of the Master of Public Health program and clinical associate professor of epidemiology at the University of Florida, Gainesville.
The median follow-up time after discharge was 4.4 days. During the study period, 45 (2.2%) patients were readmitted, with median time to readmission of 3 days.
The most common comorbidities among all 5,700 patients were hypertension (57%), obesity (41%), and diabetes (34%). As has been seen in other patient series, male sex and increasing age were associated with a higher risk for death.
The most surprising finding, Dr. Davidson said, was that fever was uncommon. “Of 5,700 patients requiring admission because of respiratory distress, only a third had fever. So fever should not be a single symptom upon which people make a decision to seek help.”
Dr. Prins was intrigued by the observation that 2% of the patients tested positive for a respiratory virus panel as well as for COVID-19. “Because of a shortage of COVID-19 testing supplies, some hospitals have been running respiratory panels before testing for COVID-19. But this study provides more evidence that a positive result on a respiratory panel does not rule out COVID-19 infection.”
The clinical situation is constantly in flux. “We’ve been seeing since March 8 that the severity of patients has lessened dramatically, and they are coming in later in the disease. Many things are changing, we hope for the better,” Dr. Davidson said.
This article was first published on Medscape.com.