J Korean Med Sci.  2021 Apr;36(15):e108. 10.3346/jkms.2021.36.e108.

A Clinical Risk Score to Predict In-hospital Mortality from COVID-19 in South Korea

• Her AY
• Bhak Y
• Jun EJ
• Yuan SL
• Garg S
• Lee S
• Bhak J
• Shin ES

• KMID: 2515042
• DOI: http://doi.org/10.3346/jkms.2021.36.e108

Abstract

Background
Early identification of patients with coronavirus disease 2019 (COVID-19) who are at high risk of mortality is of vital importance for appropriate clinical decision making and delivering optimal treatment. We aimed to develop and validate a clinical risk score for predicting mortality at the time of admission of patients hospitalized with COVID-19.
Methods
Collaborating with the Korea Centers for Disease Control and Prevention (KCDC), we established a prospective consecutive cohort of 5,628 patients with confirmed COVID-19 infection who were admitted to 120 hospitals in Korea between January 20, 2020, and April 30, 2020. The cohort was randomly divided using a 7:3 ratio into a development (n = 3,940) and validation (n = 1,688) set. Clinical information and complete blood count (CBC) detected at admission were investigated using Least Absolute Shrinkage and Selection Operator (LASSO) and logistic regression to construct a predictive risk score (COVID-Mortality Score). The discriminative power of the risk model was assessed by calculating the area under the curve (AUC) of the receiver operating characteristic curves.
Results
The incidence of mortality was 4.3% in both the development and validation set. A COVID-Mortality Score consisting of age, sex, body mass index, combined comorbidity, clinical symptoms, and CBC was developed. AUCs of the scoring system were 0.96 (95% confidence interval [CI], 0.85–0.91) and 0.97 (95% CI, 0.84–0.93) in the development and validation set, respectively. If the model was optimized for > 90% sensitivity, accuracies were 81.0% and 80.2% with sensitivities of 91.7% and 86.1% in the development and validation set, respectively. The optimized scoring system has been applied to the public online risk calculator (https://www.diseaseriskscore.com).
Conclusion
This clinically developed and validated COVID-Mortality Score, using clinical data available at the time of admission, will aid clinicians in predicting in-hospital mortality.

Keyword

COVID-19; In-hospital Mortality; Death; Prediction; Risk Score

Figure

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  Fig. 1 Receiver operating characteristic curve analysis in development set. Area under the curve of the COVID-19 in-hospital mortality score in the 3,940 patients that constituted the development set.

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  Fig. 2 Receiver operating characteristic curve analysis in validation set. Area under the curve of the COVID-19 in-hospital mortality score in the 1,688 patients that constituted the validation set.

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