Emergency room comprehensive assessment of demographic, radiological, laboratory and clinical data of patients with COVID-19: determination of its prognostic value for in-hospital mortality

Abstract

Mortality risk in COVID-19 patients is determined by several factors. The aim of our study was to adopt an integrated approach based on clinical, laboratory and chest x-ray (CXR) findings collected at the patient's admission to Emergency Room (ER) to identify prognostic factors. Retrospective study on 346 consecutive patients admitted to the ER of two North-Western Italy hospitals between March 9 and April 10, 2020 with clinical suspicion of COVID-19 confirmed by reverse transcriptase-polymerase reaction chain test (RT-PCR), CXR performed within 24 h (analyzed with two different scores) and recorded prognosis. Clinical and laboratory data were collected. Statistical analysis on the features of 83 in-hospital dead vs 263 recovered patients was performed with univariate (uBLR), multivariate binary logistic regression (mBLR) and ROC curve analysis. uBLR identified significant differences for several variables, most of them intertwined by multiple correlations. mBLR recognized as significant independent predictors for in-hospital mortality age > 75 years, C-reactive protein (CRP) > 60 mg/L, PaO₂/FiO₂ ratio (P/F) < 250 and CXR "Brixia score" > 7. Among the patients with at least two predictors, the in-hospital mortality rate was 58% against 6% for others [p < 0.0001; RR = 7.6 (4.4-13)]. Patients over 75 years had three other predictors in 35% cases against 10% for others [p < 0.0001, RR = 3.5 (1.9-6.4)]. The greatest risk of death from COVID-19 was age above 75 years, worsened by elevated CRP and CXR score and reduced P/F. Prompt determination of these data at admission to the emergency department could improve COVID-19 pretreatment risk stratification.

Keywords: Chest X-ray; Coronavirus disease 2019 (COVID-19); Outcome; Prognosis; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Fig. 1

Study flow chart

Fig. 2

ROC curves. Left panel: age (red, AUC = 0.86); Brixia Score (green, AUC = 0.84), LDH (blue, AUC = 0.81). Right panel: CPR (red, AUC = 0.89), NLR (green, AUC = 0.89), PaO₂/FiO₂ (blue, AUC = 0.82) (color figure online)

Fig. 3

Number of in-hospital mortality predictors for each patient. Top panel: distribution of the total number n of risk predictors between dead and recovered patients. Bottom panel: ROC curve testing the discriminating ability of n

Fig. 4

a 62-Year-old man who had the following values for the risk predictors when admitted to the emergency room: P/F = 417, CRP = 25.6 mg/L and Brixia score 2. Overall, the patient had no risk factor and he was discharged after recovery without the need of intensive care unit. b 67-Year-old man who had the following values: P/F = 314, CRP = 92.3 mg/L and Brixia score 7. Overall, the patient had one risk factor and was discharged after discharged after need of the intensive care unit. c 87-Year-old female who had the following values: P/F = 262, CRP = 91.2 mg/L and Brixia score 13. Overall, the patients had three risk factors and died during hospitalization