We have learned much about the novel coronavirus in the months since the start of the pandemic. But one of the major questions is one that we normally are quite comfortable with as emergency physicians: Who can be discharged, and who must be hospitalized?

While we are becoming more familiar with the risk factors for severe COVID-19 illness, including age and certain preexisting conditions, that is not the same as knowing who to admit and who to send home.

A problem noted from early in the pandemic is that some patients worsen many days after initially developing symptoms.¹ Delays in deterioration can occur with other viral illnesses but not with the characteristic pattern of COVID-19.² The common adage for mildly or moderately ill patients with influenza or stomach virus—“You’ll start to feel better in a few days”—may not apply. Despite known risk factors, young and healthy people can still get very sick without explanation, even after “turning the corner,” and others have symptoms that persist for weeks and months.³

While we are skilled in providing lifesaving care to patients with critical illness, a different challenge arises when we provide guidance and reassurance to patients who truly are sick, may indeed have early but serious disease, but are stable and do not require any services that hospitalization uniquely provides.

COVID Bouncebacks

For this reason, our team studied COVID-19 patients who return to the hospital after an initial evaluation in the emergency department.⁴ The goal was to understand how often people need hospitalization after initially appearing well enough to recover at home, as well as to identify which patients tend to worsen to the point of needing hospitalization and when that might occur. We analyzed the outcomes of 1,419 patients with COVID-19 who were evaluated and discharged from five hospital emergency departments from March through May.

The results (see Figure 1) have implications for clinicians seeking to counsel patients as well as health systems seeking to monitor the progress of patients with COVID-19. Overall, nearly 5 percent of patients returned within 72 hours and needed admission to the hospital. For context, this rate may be five times higher than that described for all ED patients.⁵ An additional 3.5 percent of patients needed admission within one week. The fact that patients were hospitalized on their second visit indicates that their illness and symptoms progressed to the point where they needed a higher level of support than they could receive at home, such as oxygen, therapeutic medications, or treatments for other chronic conditions that may have been exacerbated.