Table 1. Current overview of COVID-19 severity or mortality prediction models.

Author/setting/outcome	Score variables	Sample size (No. of participants for validation set)	Predictive performance
Liang et al.4/data from China, patients with confirmed COVID-19/in-hospital mortality	10 variables (chest radiographic abnormality, age, hemoptysis, dyspnea, unconsciousness, number of comorbidities, cancer history, neutrophil-to-lymphocyte ratio, lactate dehydrogenase, direct bilirubin)	1,590 (710)	C index 0.88 (95% CI, 0.84–0.93)
Altschul et al.5/data from US, patients with confirmed COVID-19/in-hospital mortality	6 variables (age, oxygen saturation, mean arterial pressure, blood urea nitrogen, C-Reactive protein, international normalized ratio)	4,711 (2,356)	C index 0.80 (95% CI, 0.79–0.82)
Gao et al.6/data from China, patients with confirmed COVID-19/in-hospital mortality	14 variables (age, sex, fever, sputum, consciousness, respiration rate, oxygen saturation, chronic kidney disease, number of comorbidities, platelet, blood urea nitrogen, D-dimer, albumin, lymphocyte)	2,520 (1,080)	C index 0.96 (95% CI, 0.95–0.98)
Yadaw et al.9/data from US, patients with confirmed COVID-19/in-hospital mortality	3 variables (age, minimum oxygen saturation, type of patient encounter)	3,841 (1,210)	C index 0.91 (95% CI, 0.88–0.94) (retrospective), 0.94 (95% CI, 0.90–0.97) (prospective)

COVID-19 = coronavirus disease 2019, CI = confidence interval.