Which parameters support disposition decision in suspected COVID-19 cases in the emergency department (ED): a German clinical cohort study

Abstract

Objectives: One major goal of the emergency department (ED) is to decide, whether patients need to be hospitalised or can be sent home safely. We aim at providing criteria for these decisions without knowing the SARS-CoV-2 test result in suspected cases.

Setting: Tertiary emergency medicine.

Participants: All patients were treated at the ED of the Charité during the pandemic peak and underwent SARS-CoV-2 testing. Patients with positive test results were characterised in detail and underwent a 14-day-follow-up.

Primary and secondary outcome measures: Logistic regression and classification and regression tree (CART) analyses were performed to identify predictors (primary endpoint), which confirm safe discharge. The clinical endpoint was all-cause mortality or need for mechanical ventilation during index stay or after readmission.

Results: The primary test population of suspected COVID-19 consisted of n=1255 cases, 45.2% were women (n=567). Of these, n=110 tested positive for SARS-CoV-2 (8.8%). The median age of SARS-CoV-2-positive cases was 45 years (IQR: 33-66 years), whereas the median age of the group tested negative for SARS-CoV-2 was 42 years (IQR: 30-60 years) (p=0.096). 43.6% were directly admitted to hospital care.CART analysis identified the variables oxygen saturation (<95%), dyspnoea and history of cardiovascular (CV) disease to distinguish between high and low-risk groups. If all three variables were negative, most patients were discharged from ED, and the incidence of the clinical endpoint was 0%. The validation cohort confirmed the safety of discharge using these variables and revealed an incidence of the clinical endpoint from 14.3% in patients with CV disease, 9.4% in patients with dyspnoea and 18.2% in patients with O₂ satuaration below 95%.

Conclusions: Based on easily available variables like dyspnoea, oxygen saturation, history of CV disease, approximately 25% of patients subsequently confirmed with COVID-19 can be identified for safe discharge.

Trial registration number: DRKS00023117.

Keywords: COVID-19; accident & emergency medicine; health & safety.

Figure 1

Patient flow diagram of the derivation cohort. *SARS-CoV-2 positive: n=106 positive tests performed at Charité laboratory, n=4 confirmed cases tested positive prior to their presentation in the ED (later confirmed in Charité laboratory) were also included in the analysis (total n=110). ED, emergency department.

Figure 2

Absolute number of SARS-CoV-2 negative tests (blue) and confirmed SARS-CoV-2 cases (red) in patients with ED at Charité Universitätsmedizin Berlin (CVK, CCM). CCM, Campus Charité Mitte; CVK, Campus Virchow Klinikum; ED, emergency department.

Figure 3

Classification and regression tree in the derivation cohort of Charité Universitätsmedizin Berlin. The position of the boxes on the x-axis illustrated the frequency of inpatient treatment in per cent while the size of the boxes is proportional to the size of the respective patient subgroup. Additionally to the proportion of patients who were admitted, the frequency of the clinical EP is displayed. *There was no further discriminating variable in the subgroup of patients with dyspnoea. CV, cardiovascular; EP, endpoint; nmiss, number of missing values; O₂, oxygen.

Figure 4

Classification and regression tree in the validation cohort of the EDs of the University Hospitals of Cologne, Münster, Essen and Kiel from the ReCovER registry. The position of the boxes on the x-axis illustrated the frequency of inpatient treatment in per cent while the size of the boxes is proportional to the size of the respective patient subgroup. In the low risk group, one patient had a clinical endpoint. This patient was admitted to the ward directly from the ED and had a terminal oncological disease, which led to patient’s death without ICU admission. ED, emergency department; ICU, intensive care unit.