Table 1.

Overview of selected prognostic models

Model name	Derivation country		Pre-existing or COVID-19 specific	Derivation health care setting	Derivation population	Intended moment of use	Predicted outcome	Predictors		Model type
GAL-COVID-19-mortality model [18]	Spain		COVID-19 specific model	Primary care	Adults (≥ 18 years) with confirmed COVID-19 diagnosis	First presentation with COVID-19 infection at general practitioner	Mortality (no prediction horizon reported)	• Age • Sex • Lymphoma/leukemia • Liver disease • Dementia • Ischemic heart disease • Chronic obstructive pulmonary disease • Diabetes mellitus • Chronic kidney disease		Prediction model
4C-Mortality Score [19]	UK		COVID-19 specific model	Hospital	Adults (≥ 18 years) with confirmed COVID-19 diagnosis	At hospital admission for COVID-19 infection	In-hospital mortality	• Age • Sex • Respiratory rate • Peripheral oxygen saturation on room air • Glasgow Coma Scale • Urea • C-reactive protein • Number of comorbidities (counted as chronic cardiac disease, chronic respiratory disease (excluding asthma), chronic renal disease, liver disease, dementia, chronic neurological conditions, connective tissue disease, diabetes mellitus, HIV or AIDS, malignancy, obesity)		Points-based score
NEWS2 + model [20]		UK	Pre-existing risk stratification score updated for COVID-19 patients	Hospital	Adults (≥ 18 years) admitted to the hospital with a confirmed COVID -19 diagnosis	• At hospital admission for non-nosocomial patients (i.e., community-acquired COVID infection) • At the date of symptom onset for nosocomial patients. If the date of onset was unavailable the date of positive SARS-CoV-2 RT-PCR minus 4 days was used instead	ICU admission or death within 14 days of admission	• Age • Peripheral oxygen saturation • Heart rate • Systolic blood pressure • Body temperature • Alertness • Supplemental oxygen flow rate • Urea • C-reactive protein • Estimated glomerular filtration rate • Neutrophil count • Neutrophil/lymphocyte ratio		Prediction model
Xie model [21]		China	COVID-19 specific model	Hospital	Adults (≥ 18 years) admitted to the hospital with a confirmed COVID -19 diagnosis	At hospital admission for COVID-19 infection	In-hospital mortality	• Age • Lactate dehydrogenase • Lymphocyte count • Oxygen saturation		Prediction model
Wang clinical model [22]		China	COVID-19 specific model	Hospital	Adults (≥ 18 years) admitted to the hospital with a confirmed COVID-19 diagnosis. Pregnant women were excluded	At hospital admission for COVID-19 infection	In-hospital mortality	• Age • History of hypertension • History of heart disease		Prediction model
APACHE-II Score [23]		USA	Pre-existing risk stratification score	Hospital	All newly admitted ICU patients	At admission to ICU	Mortality	• Age • Body temperature • Heart rate • Respiratory rate • Mean arterial pressure • Arterial oxygen tension • pH • Potassium • Sodium • Creatinine • Hematocrit • Leucocyte count • Glasgow Coma Scale • Chronic health evaluation		Points-based score
CURB-65 [24]		UK, New Zealand, The Netherlands	Pre-existing risk stratification score	Hospital	Patients with community-acquired pneumonia	For triage at the emergency department	Mortality (30 days)		• Age • Alertness (new confusion) • Urea • Respiratory rate • Systolic blood pressure • Diastolic blood pressure	Points-based score
SOFA Score [25]		Unclear	Pre-existing risk stratification score	Hospital	All ICU patients	At admission to and during admission at ICU	ICU-mortality		• Arterial oxygen tension • Fraction of inspired oxygen ratio • Glasgow Coma Scale • Mean arterial pressure • Administration of vasopressors • Creatinine • Bilirubin • Platelet count	Points-based score

COVID-19 Coronavirus disease of 2019, ICU Intensive care unit; RT-PCR Reverse transcription polymerase chain reaction, SARS-CoV-2 Severe acute respiratory syndrome coronavirus