Mortality risk model validation in a prospective cohort of patients from the sixth wave of the COVID-19 pandemic in a hospital emergency department

Objective. To validate risk factors for mortality in patients treated for COVID-19 in a hospital emergency department during the sixth wave of the pandemic. Method. Prospective observational noninterventional study. We included patients over the age of 18 years with a confirmed diagnosis of COVID-19 between December 1, 2021, and February 28, 2022. For each patient we calculated a risk score based on age 50 years or older (2 points) plus 1 point each for the presence of the following predictors: Barthel index less than 90 points, altered level of consciousness, ratio of arterial oxygen saturation to fraction of inspired oxygen less than 400, abnormal breath sounds, platelet concentration less than 100 x 10(9)/L, C-reactive protein level of 5 mg/dL or more, and glomerular filtration rate less than 45 mL/min. The model was assessed with the area under the receiver operating characteristic curve (AUC). Results. Of the 1156 patients included, 790 (68%) had received at least 2 vaccine doses. The probability of 30-day survival was 96%. A risk score was calculated for 609 patients. Four hundred seventeen patients were at low risk of death, 180 were at intermediate risk, and 10 were at high risk. The probability of death within 30 days was 1%, 13%, and 50% for patients in the 3 risk groups, respectively. The sensitivity, specificity, and positive and negative predictive values of a risk score of 3 points or less were 88%, 72%, 19%, 99%, respectively.The AUC for the model was 0.87. Conclusion. The risk model identified low risk of mortality and allowed us to safely discharge patients treated for COVID-19 in our tertiary-care hospital emergency department.