Study variables

We analysed patient characteristics such as demographics, vital signs, symptoms, risks for infection, comorbidities and medications. Following the 4C Mortality Score, we categorised the patients into five age groups (18–49, 50–59, 60–69, 70–79, 80+). The US standard ethnicity (Hispanic/Latinx yes/no) and race categories were combined into eight categories (Hispanic/Latinx (H/L), non-H/L white, non-H/L African American/black, non-H/L Asian, non-H/L Native American/Alaskan Native, non-H/L Pacific Islander/Native Hawaiian, non-H/L mixed and Unknown). In the analysis, we combined non-H/L Native American (0.2%), non-H/L Pacific Islander (0.2%), non-H/L mixed, other and unknown into a single group (12.8%).

All included patients had a positive reverse transcriptase PCR test (RT-PCR) test for SARS-CoV-2. Almost all the tests were performed during the ED visit, but we also included patients who had a test in a physician’s office or urgent care immediately prior to the ED visit. We excluded patients whose 30-day vital status could not be ascertained, those who died in the ED before vital signs were recorded and those who did not have full code status.