Living review
The most comprehensive systematic review of all COVID-19 related diagnostic, prognostic and general population prediction models, including accuracy, quality (risk of bias) and applicability assessment. This living review is published in BMJ.
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Key findings of the Living Review
What is a prediction model?
A prediction model combines various characteristics of a patient and his/her health to estimate an individual’s probability of having a disease, or experiencing a certain event in the future. For example, a model may inform a patient and his/her doctor that he/she has a 90% probability of having COVID-19. After the diagnosis is confirmed, another model estimates that he/she has 20% probability of dying due to COVID-19.
A valid and reliable prediction gives the true probability of a diagnosis or outcome, but this probability is inevitably uncertain for an individual patient. Importantly, however, a valid and reliable prediction supports doctors to make the best possible decisions for an individual patient. Predictions can be used in shared decision making between patients, their families, and doctors. This helps to tailor scarce healthcare resources to those who need them most.
What is the aim of the Living Review?
This Living Review provides an overview of available prediction models for COVID-19, and we performed a quality control of all models. We systematically checked potential issues with (1) the quality of the data used to build the model, (2) the quality of the predictors that form the input for the prediction, (3) the quality of the predicted outcomes, and (4) the quality of statistical data analysis.
The Living Review identifies the best available models to be used in clinical practice. Furthermore, the Living Review guides researchers to improve the quality of their future prediction model studies.
What are the findings?
We screened over 126 000 studies, where a wide array of models was included, from simple pen-and-paper scoring systems, to artificial intelligence that automatically interprets medical images.
Prediction models are abundant in medical literature. Many are freely available, for example as web applications. Although the majority of studies claim moderate to excellent predictive performance, the Living Review shows that most studies are likely optimistic and biased (i.e., containing systematic error). All types of models, including those based on advanced artificial intelligence, were prone to bias.
The best quality models were:
- The Qcovid models to predict COVID-19 vulnerability in the general population. These models could tailor the use of preventative interventions, such as vaccination and shielding.
- The PRIEST model to predict whether patients with COVID-19 will have an adverse outcome, such as death. This model can be used to triage patients with COVID-19 that go to the ER.
- The ISARIC4C Deterioration model, the Carr model and the Xie model, to predict whether patients hospitalized with COVID-19 will have an adverse outcome, such as death, critical care or ventilatory support. These models could guide doctors to make the best possible decisions for individual patients regarding, for example, intensive care support. This helps optimizing the use of scarce hospital resources.
What should happen now?
To be certain that models can benefit patients and doctors, it is important that they are extensively tested. Validation studies test the models in new patients and quantify how accurate the predictions are.
A prediction model predicts most accurately in the context where it has been developed. Before a prediction model can be used in clinical practice, we strongly recommend to perform a validation study to verify the predictions in a recent and local dataset.
We took initiative to collect and combine individual patient data from multiple studies across the world to provide such validation data and test prediction models before clinical implementation (IPDMA).
Summary details per model
| REF | OUTCOME | RISK OF BIAS |
|---|---|---|
| Abbas, Abdelsamea, et al. | covid-19 diagnosis | High |
| Abdulaal, Patel et al | mortality (in hospital) | High |
| Abdulaal, Patel et al 2 | mortality (in hospital) | High |
| Acar, Can et al | mortality (in hospital) | High |
| Al - Najjar, Al-Rousan | mortality (in or out of hospital) | High |
| Al - Najjar, Al-Rousan | other | High |
| Al Hassan, Cocks et al | other (composite) | High |
| Al Hassan, Cocks et al | other (composite) | High |
| Al Hassan, Cocks et al | other (composite) | High |
| Alafif, Alotaibi et al | other | High |
| Aliberti, Covinsky et al | #N/A | High |
| Allenbach, Saadoun et al | other (composite) | High |
| Altschul, Unda et al | mortality (in hospital) | High |
| Alvarez-Mon, Ortega et al | other (composite) | High |
| An, Lim et al | mortality (in or out of hospital) | High |
| An, Lim et al | mortality (in or out of hospital) | High |
| Angelov, Soares | covid-19 diagnosis | High |
| Anurag, Preetam | severe covid-19 | High |
| Anurag, Preetam | severe covid-19 | High |
| Anurag, Preetam | severe covid-19 | High |
| Apostolopoulos, Aznaouridis et al | covid-19 diagnosis | High |
| Apostolopoulos, Mpesiana. | covid-19 diagnosis | High |
| Ardakani, Kanafi et al | covid-19 diagnosis | High |
| Arpan, Surya et al | covid-19 diagnosis | High |
| Artero, Madrazo et al | mortality (in hospital) | High |
| Artero, Madrazo et al | mortality (in hospital) | High |
| Artero, Madrazo et al | mortality (in hospital) | High |
| Artero, Madrazo et al | mortality (in hospital) | High |
| Arvind, Kim et al | other | High |
| Assaf, Gutman et al | other | High |
| Assaf, Gutman et al | other | High |
| Assaf, Gutman et al | other | High |
| Bai, Fang et al. | progression to severe covid-19 | High |
| Bai, Wang et al. | covid-19 diagnosis | High |
| Baker, Hanrath | other | High |
| Bar, Lecourtois et al | covid-19 diagnosis | High |
| Barda, Riesel et al | mortality (in or out of hospital) | High |
| Barstugan, Ozkaya et al | covid-19 diagnosis | High |
| Bartoletti, Giannella et al | other | High |
| Bassi, Attux | covid-19 diagnosis | High |
| Batista, Miraglia et al | covid-19 diagnosis | High |
| Bello-Chavolla, Antonio-Villa | severe covid-19 | High |
| Bello-Chavolla, Antonio-Villa | severe covid-19 | High |
| Bello-Chavolla, Bahena-Lopez et al | mortality (in or out of hospital) | High |
| Bellos, Lourida et al | ICU admission | High |
| Benchoufi, Bokobza et al | other | High |
| Bennouar, Cherif et al | severe covid-19 pneumonia | High |
| Bernabeu-Wittel, Ternero-Vega | other | High |
| Bernabeu-Wittel, Ternero-Vega | other | High |
| Bernabeu-Wittel, Ternero-Vega | other | High |
| Bernabeu-Wittel, Ternero-Vega | other | High |
| Bernabeu-Wittel, Ternero-Vega | other | High |
| Bernabeu-Wittel, Ternero-Vega | other | High |
| Bertsimas, Lukin et al | mortality (in hospital) | High |
| Berzuini, Hannan et al | mortality (in hospital) | High |
| Berzuini, Hannan et al | mortality (in hospital) | High |
| Berzuini, Hannan et al | mortality (in hospital) | High |
| Bi, Su et al | progression to severe covid-19 | High |
| Boero, Rovida | other | High |
| Bolourani, Brenner et al | progression to severe covid-19 | Unclear |
| Booth, Abels et al | mortality (in hospital) | High |
| Borghesi, Maroldi | other | High |
| Borghesi, Zigliani et al | mortality (in hospital) | High |
| Born, Brandle | covid-19 diagnosis | High |
| Bradley, Frost et al | mortality (in or out of hospital) | High |
| Bradley, Frost et al | mortality (in or out of hospital) | High |
| Bradley, Frost et al | mortality (in or out of hospital) | High |
| Bradley, Frost et al | mortality (in or out of hospital) | High |
| Bradley, Frost et al | mortality (in or out of hospital) | High |
| Bradley, Frost et al | mortality (in or out of hospital) | High |
| Bradley, Frost et al | ICU admission | High |
| Bradley, Frost et al | ICU admission | High |
| Bradley, Frost et al | ICU admission | High |
| Bradley, Frost et al | mortality (in or out of hospital) | High |
| Bradley, Frost et al | mortality (in or out of hospital) | High |
| Bradley, Frost et al | ICU admission | High |
| Brinati, Campagner et al | covid-19 diagnosis | High |
| Brinati, Campagner et al | covid-19 diagnosis | High |
| Bukhari, Bukhari et al. | covid-19 diagnosis | High |
| Burdick, Lam et al | progression to severe covid-19 | High |
| Burdick, Lam et al | progression to severe covid-19 | High |
| Burian, Jungmann et al | ICU admission | High |
| Burke, Freeman et al | other (composite) | High |
| Cao, Li et al | severe covid-19 pneumonia | High |
| Cao, Zhang et al | mortality (in hospital) | High |
| Carmelo, Oliveiros et al. | mortality (in or out of hospital) | High |
| Caro-Codn, Lip et al | mortality (in hospital) | Unclear |
| Caro-Codn, Lip et al | mortality (in hospital) | Unclear |
| Caro-Codn, Lip et al | mortality (in hospital) | Unclear |
| Caro-Codn, Lip et al | other | Unclear |
| Caro-Codn, Lip et al | other | Unclear |
| Caro-Codn, Lip et al | other | Unclear |
| Carr, Bendayan et al | other (composite) | Low |
| Castiglioni, Ippolito et al | covid-19 diagnosis | High |
| Cecconi, Piovani et al | other (composite) | High |
| Cetinkal, Balaban Kocas, et al | other (composite) | High |
| Cetinkal, Balaban Kocas, et al | other (composite) | High |
| Cetinkal, Balaban Kocas, et al | other (composite) | High |
| Cetinkal, Balaban Kocas, et al | other (composite) | High |
| Chaganti, Balachandran, et al. | other | High |
| Chaganti, Balachandran, et al. | other | High |
| Chaganti, Balachandran, et al. | other | High |
| Chaganti, Balachandran, et al. | other | High |
| Chao, Fang, et al | ICU admission | High |
| Chao, Fang, et al | ICU admission | High |
| Chao, Fang, et al | ICU admission | High |
| Chassagnon, Vakalopoulou, et al | other (composite) | High |
| Chassagnon, Vakalopoulou, et al | other (composite) | High |
| Chen et al. Risk factors for mortality | mortality (in hospital) | High |
| Chen et al. Risk factors for mortality | mortality (in hospital) | High |
| Chen et al. Risk factors for mortality | mortality (in hospital) | High |
| Chen, et al. Development and validation of a nomogram | mortality (in hospital) | High |
| Chen, et al. Predicting severe or critical symptoms | severe covid-19 | High |
| Chen, Tang et al | covid-19 diagnosis | High |
| Chen, Wu et al. | covid-19 pneumonia | High |
| Chen, Zeng | other | High |
| Cheng, et al. Diagnostic performance of unitial blood urea nitrogen | mortality (in hospital) | High |
| Cheng, et al. Pneumonia scoring systems | mortality (in hospital) | High |
| Cheng, et al. Pneumonia scoring systems | mortality (in hospital) | High |
| Cheng, et al. Pneumonia scoring systems | mortality (in hospital) | High |
| Cheng, et al. Pneumonia scoring systems | other | High |
| Cheng, et al. Pneumonia scoring systems | other | High |
| Cheng, et al. Pneumonia scoring systems | other | High |
| Cheng, et al. Pneumonia scoring systems | other | High |
| Cheng, et al. Pneumonia scoring systems | other | High |
| Cheng, et al. Pneumonia scoring systems | other | High |
| Cheng, Joshi et al | ICU admission | High |
| Cho et al. Prognosis score system | mortality (in or out of hospital) | High |
| Choi, Ahn et al | progression to severe covid-19 | High |
| Choi, Ahn et al | progression to severe covid-19 | High |
| Choi, Ahn et al | progression to severe covid-19 | High |
| Choi, Ahn et al | progression to severe covid-19 | High |
| Choi, Ahn et al | progression to severe covid-19 | High |
| Choi, Ahn et al | progression to severe covid-19 | High |
| Choi, Ahn et al | progression to severe covid-19 | High |
| Chow et al. Development and externally | other (composite) | High |
| Chowdhury, Rahman et al. | #N/A | High |
| Chowdhury, Rahman et al. | #N/A | High |
| Chowdhury, Rahman et al. | other | High |
| Chowdhury, Rahman et al. | other | High |
| õnar et al. Is prognostic nutritional index | mortality (in hospital) | High |
| õnar et al. Is prognostic nutritional index | mortality (in hospital) | High |
| õnar et al. Is prognostic nutritional index | mortality (in hospital) | High |
| Clemency, Varughese et al | covid-19 diagnosis | High |
| Clemency, Varughese et al | covid-19 diagnosis | High |
| Clift, Coupland et al | mortality (in or out of hospital) | Low |
| Clift, Coupland et al | mortality (in or out of hospital) | Low |
| Clift, Coupland et al | hospital admission for covid-19 pneumonia | Low |
| Clift, Coupland et al | hospital admission for covid-19 pneumonia | Low |
| Colombi, Bodini et al | other (composite) | High |
| Colombi, Bodini et al | other (composite) | High |
| Covino, Matteis et al | mortality (in hospital) | High |
| Covino, Matteis et al | mortality (in hospital) | High |
| Covino, Matteis et al | mortality (in hospital) | High |
| Covino, Matteis et al | mortality (in hospital) | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | ICU admission | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Covino, Sandroni et al | mortality (in hospital) | High |
| Dai, Zeng et al | severe covid-19 | High |
| Dai, Zeng et al | severe covid-19 | High |
| Das, Mishra | mortality (in or out of hospital) | High |
| De Giorgi, Fabbian et al | mortality (in hospital) | High |
| DeCapprio, Gartner, et al | hospital admission for covid-19 pneumonia | High |
| DeCapprio, Gartner, et al | hospital admission for covid-19 pneumonia | High |
| DeCapprio, Gartner, et al | hospital admission for covid-19 pneumonia | High |
| Diaz-Quijano, Nunes da Silva et al | covid-19 diagnosis | High |
| Ding, Li et al | mortality (in hospital) | High |
| Doganci, Ince et al | mortality (in hospital) | High |
| Dong, Sun et al | mortality (in hospital) | High |
| Dong, Zhou et al | severe covid-19 | High |
| Douville, Douville et al | other | High |
| Dujardin, Hilderink et al | other | High |
| Ebrahimian, Homayounieh et al | mortality (in hospital) | High |
| Ebrahimian, Homayounieh et al | mortality (in hospital) | High |
| El Asnaoui, Chawki et al | other | High |
| El-Solh, Lawson et al | mortality (in hospital) | Unclear |
| El-Solh, Lawson et al | mortality (in hospital) | Unclear |
| El-Solh, Lawson et al | mortality (in hospital) | Unclear |
| El-Solh, Lawson et al | mortality (in hospital) | Unclear |
| Espana, Bilbao et al | mortality (in or out of hospital) | High |
| Espana, Bilbao et al | mortality (in or out of hospital) | High |
| Esposito, Palmisano et al | mortality (in or out of hospital) | High |
| Fan, Hao et al | progression to severe covid-19 | High |
| Fan, Tu et al | mortality (in hospital) | High |
| Fan, Zhu et al. | other | High |
| Feng, Huang et al | covid-19 pneumonia | High |
| Feng, Yu et al | severe covid-19 pneumonia | High |
| Fernandes, de Oliveira et al | mortality (in hospital) | High |
| Fernandes, de Oliveira et al | ICU admission | High |
| Fernandes, de Oliveira et al | other | High |
| Fernandez, Obiechina et al | mortality (in hospital) | High |
| Ferrari, Milic et al | severe covid-19 pneumonia | Unclear |
| Fisman, Greer et al | mortality (in or out of hospital) | High |
| Flores, Dayan et al | other (composite) | High |
| Foieni, Sala et al | mortality (in hospital) | Unclear |
| Fu, Li et al | progression to severe covid-19 | High |
| Fu, Yi et al. | covid-19 diagnosis | High |
| Fumagalli, Rozzini | mortality (in or out of hospital) | High |
| Galloway, Norton et al | other (composite) | High |
| Gao, Cai et al | mortality (in hospital) | Unclear |
| Garca Clemente, Herrero Huertas 2020 | mortality (in hospital) | Unclear |
| Garca Clemente, Herrero Huertas 2020 | ICU admission | High |
| Garca Clemente, Herrero Huertas 2020 | mortality (in hospital) | Unclear |
| Garca Clemente, Herrero Huertas 2020 | ICU admission | High |
| Garca Clemente, Herrero Huertas 2020 | mortality (in hospital) | Unclear |
| Garca Clemente, Herrero Huertas 2020 | ICU admission | High |
| Garca Clemente, Herrero Huertas 2020 | mortality (in hospital) | Unclear |
| Garca Clemente, Herrero Huertas 2020 | ICU admission | High |
| Garibaldi 2020 | other (composite) | High |
| Gavelli 2021 | other (composite) | High |
| Gavelli 2021 | mortality (in hospital) | High |
| Gerotziafas 2020 | other | High |
| Gezer, Ergan et al | covid-19 diagnosis | High |
| Gidari, de Socio et al | ICU admission | High |
| Gidari, de Socio et al | ICU admission | High |
| Goncalves, Baggio 2021 | other | High |
| Gong, Ou et al | progression to severe covid-19 | High |
| Goodacre, Thomas 2021 | other (composite) | Low |
| Gozes, Frid-Adar et al | covid-19 diagnosis | High |
| Gozes, Frid-Adar et al. | covid-19 diagnosis | High |
| Guan, Zhang 2021 | mortality (in hospital) | High |
| Gude, Riveiro 2020 | other (composite) | Unclear |
| Gude-Sampedro, Fernndez-Merino 2020 | mortality (in hospital) | Unclear |
| Gude-Sampedro, Fernndez-Merino 2020 | ICU admission | High |
| Gude-Sampedro, Fernndez-Merino 2020 | hospital admission for covid-19 pneumonia | Unclear |
| Gue, Tennyson 2020 | mortality (in or out of hospital) | High |
| Guiot, Vaidyanathan et al. | covid-19 diagnosis | High |
| Guo, Liu et al. | progression to severe covid-19 | High |
| Guo, Xiong et al | severe covid-19 pneumonia | High |
| Gupta, Harrison et al | other | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | other (composite) | Low |
| Gupta, Marks et al | mortality (in hospital) | Low |
| Gupta, Marks et al | mortality (in hospital) | Low |
| Gupta, Marks et al | mortality (in or out of hospital) | Low |
| Gupta, Marks et al | mortality (in or out of hospital) | Low |
| Gupta, Marks et al | mortality (in or out of hospital) | Low |
| Gupta, Marks et al | mortality (in hospital) | Low |
| Gupta, Marks et al | progression to severe covid-19 | Low |
| Gupta, Marks et al | progression to severe covid-19 | Low |
| Gupta, Marks et al | mortality (in or out of hospital) | Low |
| Gupta, Marks et al | mortality (in hospital) | Low |
| Gupta, Marks et al | mortality (in or out of hospital) | Low |
| Gupta, Marks et al | other | Low |
| Hachim, Hachim et al | ICU admission | High |
| Haimovich, Ravindra et al | severe covid-19 | High |
| Hajifathalian, Sharaiha et al | mortality (in or out of hospital) | High |
| Hajifathalian, Sharaiha et al | mortality (in or out of hospital) | High |
| Halalau, Imam et al | hospital admission for covid-19 pneumonia | High |
| Halalau, Imam et al | mortality (in hospital) | High |
| Hao, Sotudian et al | hospital admission for covid-19 pneumonia | High |
| Hao, Sotudian et al | ICU admission | High |
| Hao, Sotudian et al | other | High |
| Hassanien, Mahdy et al. | other | Unclear |
| He, Zhang et al | mortality (in hospital) | High |
| He, Zhang et al | other | High |
| Hectors, Riyahi et al | other | High |
| Heo, Han et al | other (composite) | High |
| Heo, Park et al | hospital admission for covid-19 pneumonia | High |
| Ho, Park et al | other (composite) | High |
| Ho, Park et al | other (composite) | High |
| Holten, Nore et al | severe covid-19 | High |
| Holten, Nore et al | severe covid-19 | High |
| Holten, Nore et al | severe covid-19 | High |
| Holten, Nore et al | severe covid-19 | High |
| Holten, Nore et al | severe covid-19 | High |
| Hong, Wu et al | length of hospital stay | High |
| Hu, Deng et al | severe covid-19 | High |
| Hu, Du et al | severe covid-19 | High |
| Hu, Liu et al | mortality (in hospital) | High |
| Hu, Ni et al | mortality (in hospital) | High |
| Hu, Ni et al | mortality (in hospital) | High |
| Hu, Ni et al | mortality (in hospital) | High |
| Hu, Ni et al | mortality (in hospital) | High |
| Hu, Ni et al | mortality (in hospital) | High |
| Hu, Ruan et al | covid-19 diagnosis | High |
| Hu, Yao et al | mortality (in hospital) | High |
| Hu, Yao et al | mortality (in hospital) | High |
| Huang, Cai, et al. | severe covid-19 pneumonia | High |
| Huang, Cheng et al | progression to severe covid-19 | High |
| Huang, Cheng et al | progression to severe covid-19 | High |
| Huang, Wang et al | covid-19 diagnosis | High |
| Huang, Yang et al | other (composite) | High |
| Huang, Zheng et al | other | High |
| Iijima, Okamoto et al | progression to severe covid-19 | High |
| Iijima, Okamoto et al | other | High |
| Ikemura, Bellin et al | mortality (in or out of hospital) | Unclear |
| Ikemura, Bellin et al | mortality (in or out of hospital) | Unclear |
| Imran, Posokhova, et al. | covid-19 diagnosis | High |
| Islam, Fleischer | covid-19 diagnosis | High |
| Jain, Kansal et al | mortality (in hospital) | High |
| Jamal, Doi et al | progression to severe covid-19 | High |
| Jang, Hur et al | other (composite) | High |
| Jang, Hur et al | mortality (in or out of hospital) | High |
| Jang, Hur et al | ICU admission | High |
| Jang, Hur et al | other | High |
| Jang, Hur et al | other | High |
| Jehi, Ji et al | covid-19 diagnosis | Unclear |
| Jehi, Ji, et al | hospital admission for covid-19 pneumonia | High |
| Ji, Zhang et al | progression to severe covid-19 | High |
| Jiang, Coffee et al | other | High |
| Jiang, Coffee et al | other | High |
| Jiang, Coffee et al | other | High |
| Jiang, Coffee et al | other | High |
| Jiang, Coffee et al | other | High |
| Jiang, Coffee et al | other | High |
| Jiang, Hu et al | other | High |
| Jimenez_Solem, Petersen et al | hospital admission for covid-19 pneumonia | High |
| Jimenez_Solem, Petersen et al | ICU admission | High |
| Jimenez_Solem, Petersen et al | mortality (in or out of hospital) | High |
| Jimenez_Solem, Petersen et al | other | High |
| Jin, Chen et al. | covid-19 diagnosis | High |
| Jin, Wang et al. | covid-19 pneumonia | High |
| Joshi, pejaver et al | covid-19 diagnosis | High |
| Kaeuffer, Ruch, et al | severe covid-19 | High |
| Kahn, Shah et al. | covid-19 diagnosis | High |
| Kamran, Humayun Mirza, et al | other | High |
| Kana, Kana et al. | covid-19 diagnosis | High |
| Kang, Chen et al | progression to severe covid-19 | High |
| Karim, Dhmen et al | covid-19 diagnosis | High |
| Kattan, Ji, et al | other (composite) | Unclear |
| Kim, Han et al | other (composite) | High |
| Kimura-Sandoval, Arevalo-Molina, et al | mortality (in hospital) | High |
| Kimura-Sandoval, Arevalo-Molina, et al | other | High |
| King, Yoon, et al | mortality (in or out of hospital) | High |
| Kirsch, Aziz et al. | other | High |
| Kivrak, Guldogan, et al. | mortality (in or out of hospital) | Unclear |
| Knight, Ho et al | mortality (in hospital) | Unclear |
| Ko, Chung et al | covid-19 pneumonia | High |
| Ko, Chung, et al. | mortality (in hospital) | High |
| Kodoma, Obinata, et al. | progression to severe covid-19 | High |
| Kostakis, Smith, et al. | other (composite) | High |
| Kumar, Arora et al. | covid-19 diagnosis | High |
| Kumar, Arora et al. | covid-19 diagnosis | High |
| Kurstjens, van der Horst et al. | covid-19 diagnosis | High |
| Laguna-Goya, Utrero-Rico, et al | mortality (in hospital) | High |
| Lasbleiz, Cariou, et al. | hospital admission for covid-19 pneumonia | High |
| Lassau, Ammari, et al. | severe covid-19 | High |
| Levine, Lipsitz, et al. | other (composite) | High |
| Levy, Richardson et al. | mortality (in hospital) | High |
| Levy, Richardson et al. | mortality (in hospital) | High |
| Levy, Richardson et al. | mortality (in hospital) | High |
| Levy, Richardson et al. | mortality (in hospital) | High |
| Li, Chen et al | mortality (in hospital) | High |
| Li, Fang et al | mortality (in hospital) | High |
| Li, Fang, et al. | other | High |
| Li, Ge et al | ICU admission | High |
| Li, Ge et al | ICU admission | High |
| Li, Ge et al | mortality (in hospital) | High |
| Li, Ge et al | mortality (in hospital) | High |
| Li, Horowitz et al | other | High |
| Li, Horowitz et al | other | High |
| Li, Lin et al | mortality (in hospital) | High |
| Li, Qin et al. | covid-19 diagnosis | High |
| Li, Wang et al | other | High |
| Li, Wang et al | other | High |
| Li, Wang et al | other | High |
| Li, Wang et al | other | High |
| Li, Wang et al | other | High |
| Li, Yang et al | mortality (in hospital) | High |
| Li, Zeng et al | covid-19 pneumonia | High |
| Li, Zhang et al | severe covid-19 | High |
| Li, Zhang, et al. | mortality (in hospital) | High |
| Li, Zhong et al | severe covid-19 | High |
| Li, Zhu et al. | other | High |
| Liang, He et al | other | High |
| Liang, Liang et al | other (composite) | High |
| Liang, Yao, et al. | progression to severe covid-19 | High |
| Linssen, Ermens et al | other (composite) | High |
| Liu et al, CD8+ T cels predicted the | severe covid-19 pneumonia | High |
| Liu et al, Development and valid | other (composite) | High |
| Liu et al, Diagnostic Performance | mortality (in hospital) | High |
| Liu et al, Evaluation of the risk pre | mortality (in hospital) | High |
| Liu et al, Evaluation of the risk pre | mortality (in hospital) | High |
| Liu et al, Evaluation of the risk pre | mortality (in hospital) | High |
| Liu et al, Evaluation of the risk pre | mortality (in hospital) | High |
| Liu et al, Evaluation of the risk pre | mortality (in hospital) | High |
| Liu et al, Predictive Performance | mortality (in hospital) | High |
| Liu et al, Predictive Performance | mortality (in hospital) | High |
| Liu et al: A nomogram for predi | mortality (in hospital) | High |
| Liu et al: A nomogram for predi | mortality (in hospital) | High |
| Liu H et al. Development and valid | mortality (in hospital) | High |
| Liu, Fang et al. | mortality (in hospital) | High |
| Liu, Li et al | severe covid-19 | High |
| Liu, Shi et al | severe covid-19 | High |
| Liu, Wang et al | other | High |
| Liu, Wang et al | other | High |
| Liu, Wang et al | other | High |
| Liu, Zhang et al | other (composite) | High |
| Liu, Zhang et al | other (composite) | High |
| Liu, Zhang et al | other (composite) | High |
| Liu; A simple nomogram for predi | other (composite) | High |
| Lopez-Rincon, Tonda et al | covid-19 diagnosis | High |
| Lorente, High serum nitrates | mortality (in or out of hospital) | High |
| Lorente-Ros, Ruiz et al | mortality (in or out of hospital) | High |
| Lorente-Ros, Ruiz et al | mortality (in or out of hospital) | high |
| Lu, Hu et al. | mortality (in or out of hospital) | High |
| Lundon, A Decision Aide for the | mortality (in or out of hospital) | High |
| Luo , Luo et al. | covid-19 pneumonia | High |
| Luo, Liu et al. | mortality (in hospital) | High |
| Luo, Liu et al. | mortality (in hospital) | Unclear |
| Luo, Mao et al | mortality (in hospital) | High |
| Luo, Ying et al. | covid-19 diagnosis | High |
| Lyu, Lui et al | severe covid-19 pneumonia | High |
| Lyu, Lui et al | severe covid-19 pneumonia | High |
| Ma, Gong et al | severe covid-19 | high |
| Ma, Li et al | mortality (in or out of hospital) | High |
| Ma, Wang et al | mortality (in hospital) | High |
| Magro, Zuccaro et al | mortality (in hospital) | Unclear |
| Manocha, Kirzner et al | mortality (in hospital) | high |
| Martin, Nateqi, et al. | covid-19 diagnosis | High |
| Matos J et al. | other | High |
| Mazzaccaro, Giacomazzi et al | ICU admission | High |
| Mazzaccaro, Giacomazzi et al | mortality (in hospital) | High |
| Mazzaccaro, Giacomazzi et al | ICU admission | High |
| Mazzaccaro, Giacomazzi et al | mortality (in hospital) | High |
| Mazzaccaro, Giacomazzi et al | other | High |
| Mazzaccaro, Giacomazzi et al | other | High |
| McElvaney, Hobbs et al | other | High |
| McRae, Dapkins et al | severe covid-19 | High |
| McRae, Dapkins et al | mortality (in hospital) | High |
| McRae, Simmons | mortality (in hospital) | High |
| Mei, Hu et al | mortality (in hospital) | High |
| Mei, Hu et al | mortality (in hospital) | Unclear |
| Mei, Lee et al | covid-19 diagnosis | High |
| Mei, Wang et al | mortality (in or out of hospital) | High |
| Mejia-Vilet, Cordova-Sanchez et al | ICU admission | High |
| Mejia-Vilet, Cordova-Sanchez et al | ICU admission | High |
| Mejia-Vilet, Cordova-Sanchez et al | ICU admission | High |
| Mejia-Vilet, Cordova-Sanchez et al | ICU admission | High |
| Mejia-Vilet, Cordova-Sanchez et al | ICU admission | High |
| Mejia-Vilet, Cordova-Sanchez et al | ICU admission | High |
| Mejia-Vilet, Cordova-Sanchez et al | ICU admission | High |
| Mejia-Vilet, Cordova-Sanchez et al | ICU admission | High |
| Meng, Wang et al. | covid-19 diagnosis | High |
| Menni, Valdes et al. | covid-19 diagnosis | High |
| Moutounet-Cartan | covid-19 pneumonia | High |
| Muhammad, Milon Islam et al | mortality (in or out of hospital) | High |
| Muhammad, Milon Islam et al | mortality (in or out of hospital) | High |
| Muhammad, Milon Islam et al | mortality (in or out of hospital) | High |
| Muhammad, Milon Islam et al | mortality (in or out of hospital) | High |
| Muhammad, Milon Islam et al | mortality (in or out of hospital) | High |
| Muhammad, Milon Islam et al | mortality (in or out of hospital) | High |
| Murphy, Smits et al | covid-19 diagnosis | High |
| Myrstad, Ihle-Hansen et al | other (composite) | High |
| Myrstad, Ihle-Hansen et al | other (composite) | High |
| Myrstad, Ihle-Hansen et al | other (composite) | High |
| Myrstad, Ihle-Hansen et al | severe covid-19 | High |
| Myrstad, Ihle-Hansen et al | mortality (in hospital) | High |
| Nagant, Ponthieux et al | other (composite) | High |
| Nagant, Ponthieux et al | other (composite) | High |
| Nemati, Ansari et al | length of hospital stay | High |
| Nemati, Ansari et al | discharge from hospital | High |
| Nemati, Ansari et al | discharge from hospital | High |
| Nemati, Ansari et al | discharge from hospital | High |
| Nemati, Ansari et al | discharge from hospital | High |
| Nemati, Ansari et al | discharge from hospital | High |
| Nemati, Ansari et al | discharge from hospital | High |
| Nguyen, Corre et al | other (composite) | High |
| Nicholson, Wooster et al | mortality (in hospital) | High |
| Nicholson, Wooster et al | other | High |
| Ning, Lei et al | severe covid-19 pneumonia | High |
| Niu, Zhan et al | mortality (in hospital) | High |
| Nunez-Gil, Fernandez-Perez et al | mortality (in hospital) | High |
| Obeid, Davis et al | covid-19 diagnosis | High |
| Ozturk, Talo et al. | covid-19 pneumonia | High |
| Pan, Cheng, et al | mortality (in hospital) | High |
| Pan, Li, et al | mortality (in hospital) | High |
| Parchure, Joshi, et al | mortality (in hospital) | High |
| Payn-Perna, Prez, et al | other | High |
| Pourhomayoun, Shakibi et al | mortality (in or out of hospital) | High |
| Pu, Leader et al | covid-19 diagnosis | High |
| Qi, Jiang et al. | length of hospital stay | High |
| Qi, Jiang et al. | length of hospital stay | High |
| Qin, Li, et al | other (composite) | High |
| Qin, Liu, et al | mortality (in hospital) | High |
| Quiroz, Feng, et al | severe covid-19 | High |
| Rahimzadeh, Attar | covid-19 pneumonia | High |
| Rajaraman, Antani | covid-19 pneumonia | High |
| Rajaraman, Antani | covid-19 pneumonia | High |
| Razavian, Major, et al | other | High |
| Rechtman, Curtin, et al | mortality (in hospital) | Unclear |
| Rehman, Naz et al | covid-19 diagnosis | High |
| Rehman, Naz et al | covid-19 diagnosis | High |
| Rehman, Naz et al | covid-19 diagnosis | High |
| Rehman, Naz et al | covid-19 diagnosis | High |
| Rehman, Naz et al | covid-19 diagnosis | High |
| Riveiro-Barciela, Labrador-Horrillo, et al | other (composite) | High |
| Riveiro-Barciela, Labrador-Horrillo, et al | other (composite) | High |
| Rodriguez-Nava, Yanez-Bello et al. | mortality (in hospital) | High |
| Rodriguez-Nava, Yanez-Bello et al. | mortality (in hospital) | High |
| Rodriguez-Nava, Yanez-Bello et al. | other | High |
| Roimi, Gutman et al. | other | High |
| Roland, Gurrola et al. | covid-19 diagnosis | High |
| Ruocco, McCullough et al | mortality (in hospital) | High |
| Ryan, Lam et al | mortality (in hospital) | High |
| Ryan, Lam et al | mortality (in hospital) | High |
| Ryan, Lam et al | mortality (in hospital) | High |
| Ryan, Lam et al | mortality (in hospital) | High |
| Ryan, Minc et al. | severe covid-19 | High |
| Saberian, Tavakoli et al | mortality (in or out of hospital) | High |
| Saberian, Tavakoli et al | mortality (in or out of hospital) | High |
| Saberian, Tavakoli et al | mortality (in or out of hospital) | High |
| Sakar, Chakrabarti | mortality (in or out of hospital) | High |
| Salahshour, Mehrabinejad et al | mortality (in hospital) | High |
| Sanchez-Montanes, Rodriquez-Belenguer et al. | mortality (in hospital) | High |
| Sang, Sun et al | mortality (in hospital) | High |
| Sang, Sun et al | other | High |
| Saridaki; Metallidis | other (composite) | High |
| Saridaki; Metallidis | other | High |
| Satici, Demirkol et al | mortality (in or out of hospital) | High |
| Satici, Demirkol et al | mortality (in or out of hospital) | High |
| Satici, Demirkol et al | mortality (in or out of hospital) | High |
| Schalekamp, Huisman et al. | other (composite) | High |
| Schoning et al | other (composite) | High |
| Sensusiati et al | mortality (in hospital) | High |
| Shan, Gao et al. | other | High |
| Shang, Liu et al | mortality (in hospital) | High |
| Sharp, Huang et al | other (composite) | High |
| Shashikumar, Wardi et al | other | High |
| Shi, Pandita et al | mortality (in hospital) | High |
| Shi, Pandita et al | mortality (in hospital) | High |
| Shi, Pandita et al | mortality (in hospital) | High |
| Shi, Pandita et al | mortality (in hospital) | High |
| Shi, Pandita et al | mortality (in hospital) | High |
| Shi, Xia et al. | covid-19 pneumonia | High |
| Shi, Yu et al. | other | High |
| Shoer, Karady et al | covid-19 diagnosis | High |
| Singh, Kumar et al | covid-19 diagnosis | High |
| Singh, Valley et al | other (composite) | High |
| Soares, Villavicencio et al | covid-19 diagnosis | High |
| Song, Dong et al | mortality (in hospital) | High |
| Song, Wang et al | covid-19 diagnosis | High |
| Song, Xu et al. | covid-19 diagnosis | High |
| Soto-Mota, Marfil-Garza et al | mortality (in hospital) | High |
| Sourij, Aziz et al | mortality (in hospital) | High |
| Sun, Hong et al | mortality (in hospital) | High |
| Sun, Jain et al | other (composite) | High |
| Sun, Koh, et al. | covid-19 diagnosis | High |
| Sun, Koh, et al. | covid-19 diagnosis | High |
| Sun, Koh, et al. | covid-19 diagnosis | High |
| Sun, Koh, et al. | covid-19 diagnosis | High |
| Sun, Song et al. | severe covid-19 | High |
| Tabatabai, Ghneim et al | mortality (in hospital) | High |
| Tanbo_a, Canpolat et al | mortality (in hospital) | High |
| Tanbo_a, Canpolat et al | mortality (in hospital) | High |
| Tang, Zhao et al. | other | High |
| Toh and Brody | severe covid-19 | High |
| Toraih, Elshazli et al | other (composite) | High |
| Tordjmann, Mekki et al | covid-19 diagnosis | High |
| Torres-Macho, Ryan et al | mortality (in or out of hospital) | High |
| Tsui, Lui et al | other | High |
| Tsui, Lui et al | other | High |
| Tuncer, Dogan et al. | covid-19 pneumonia | High |
| Ucar, Korkmaz | covid-19 diagnosis | High |
| Vaid, Jaladanki et al. | mortality (in hospital) | High |
| Vaid, Jaladanki et al. | mortality (in hospital) | High |
| Vaid, Kalantar et al. | covid-19 pneumonia | High |
| Vaid, Somani et al. | mortality (in hospital) | High |
| Vaid, Somani et al. | mortality (in hospital) | High |
| Vaid, Somani et al. | mortality (in hospital) | High |
| Vaid, Somani et al. | mortality (in hospital) | High |
| Vaid, Somani et al. | other | High |
| Vaid, Somani et al. | other | High |
| Vaid, Somani et al. | other | High |
| Vaid, Somani et al. | other | High |
| van Dam, Zelis et al. | other (composite) | High |
| van Dam, Zelis et al. | mortality (in or out of hospital) | High |
| van de Sande, van Genderen et al. | other | High |
| Varol, Hakoglu et al. | mortality (in or out of hospital) | High |
| Vazquez Guillamet, Vazquez Guillamet et al. | other (composite) | High |
| Vazquez Guillamet, Vazquez Guillamet et al. | mortality (in hospital) | High |
| Vazquez Guillamet, Vazquez Guillamet et al. | other | High |
| Vizcaychipi, Shovlin ___et al | other | High |
| Vultaggio, Vivarelli et al. | other (composite) | High |
| Wang, Zhong et al | mortality (in hospital) | High |
| Wang, Deng et al | severe covid-19 | High |
| Wang, He et al | mortality (in hospital) | High |
| Wang, Hou et al. | mortality (in hospital) | High |
| Wang, Kang et al. | covid-19 diagnosis | High |
| Wang, Liu et al | covid-19 diagnosis | High |
| Wang, Lv et al | mortality (in hospital) | High |
| Wang, Lv et al | mortality (in hospital) | High |
| Wang, Lv et al | mortality (in hospital) | High |
| Wang, Lv et al | mortality (in hospital) | High |
| Wang, Lv et al | mortality (in hospital) | High |
| Wang, Lv et al | mortality (in hospital) | High |
| Wang, Lv et al | mortality (in hospital) | High |
| Wang, Paschalidis et al | mortality (in hospital) | High |
| Wang, Paschalidis et al | mortality (in hospital) | High |
| Wang, Paschalidis et al | mortality (in hospital) | High |
| Wang, Sha et al | other (composite) | High |
| Wang, Sha et al | other (composite) | High |
| Wang, Weng, et al. | covid-19 pneumonia | High |
| Wang, Zha et al. | covid-19 diagnosis | High |
| Wang, Zha et al. | length of hospital stay | High |
| Wang, Zhang et al | mortality (in or out of hospital) | High |
| Wang, Zuo et al | mortality (in hospital) | High |
| Wang, Zuo et al | mortality (in hospital) | High |
| Weng, Chen et al | mortality (in hospital) | High |
| Wollenstein - Betech 2020 | mortality (in hospital) | High |
| Wollenstein - Betech 2020 | other | High |
| Wollenstein-Betecha, Cassandras et al | hospital admission for covid-19 pneumonia | High |
| Wollenstein-Betecha, Cassandras et al | mortality (in or out of hospital) | High |
| Wollenstein-Betecha, Cassandras et al | ICU admission | High |
| Wollenstein-Betecha, Cassandras et al | mortality (in or out of hospital) | High |
| Wollenstein-Betecha, Cassandras et al | ICU admission | High |
| Wollenstein-Betecha, Cassandras et al | other | High |
| Wollenstein-Betecha, Cassandras et al | other | High |
| Wu, Du et al | progression to severe covid-19 | High |
| Wu, Gao, et al | covid-19 diagnosis | High |
| Wu, Hui, et al | covid-19 pneumonia | High |
| Wu, Wang et al. 2020 | other (composite) | High |
| Wu, Wang et al. 2020 | other (composite) | High |
| Wu, Wang et al. 2020 | other (composite) | High |
| Wu, Wang et al. 2020 | other (composite) | High |
| Wu, Wang et al. 2020 | other (composite) | High |
| Wu, Wang et al. 2020 | other (composite) | High |
| Wu, Yang et al. 2020 | severe covid-19 | High |
| Wu, Zhang et al. 2020 | progression to severe covid-19 | High |
| Wu, Zhang et al. 2020 | mortality (after discharge) | High |
| Wu, Zhang et al. 2020 | progression to severe covid-19 | High |
| Wu, Zhang et al. 2020 | mortality (after discharge) | High |
| Wu, Zhang et al. 2020 | mortality (after discharge) | High |
| Wu, Zhang et al. 2020 | progression to severe covid-19 | High |
| Wu, Zhang et al. 2020 | mortality (after discharge) | High |
| Wu, Zhang et al. 2020 | mortality (after discharge) | High |
| Wu, Zhang, et al. | covid-19 diagnosis | High |
| Wu, Zhou et al. 2020 | mortality (in hospital) | High |
| Xia, Zhang et al. 2021 | other | high |
| Xiao, Zhang et al. 2020 | severe covid-19 | High |
| Xie, Hou et al | mortality (in hospital) | High |
| Xie, Hungerford et al. | mortality (in hospital) | High |
| Xie, Shi et al | other | High |
| Xu, Cui et al | other | High |
| Xu, Hou et al | mortality (in hospital) | HIgh |
| Xu, Hou et al | ICU admission | High |
| Xu, Jiang et al. | covid-19 diagnosis | High |
| Xu, Yang et al | other | High |
| Xue, Gan et al | progression to severe covid-19 | High |
| Yadaw, Li et al | mortality (in or out of hospital) | High |
| Yan, Zhang et al. | mortality (in or out of hospital) | High |
| Yang, Shen, et al | severe covid-19 | High |
| Yang, Wang, et al | severe covid-19 | High |
| Ying (Song), Zheng et al. | covid-19 diagnosis | High |
| Ying (Song), Zheng et al. | covid-19 diagnosis | High |
| Yu, let, et al | mortality (in hospital) | High |
| Yu, Nie et al | other | High |
| Yu, Shao et al. | severe covid-19 | High |
| Yu, Wang et al | progression to severe covid-19 | High |
| Yu, Zhu et al | mortality (in hospital) | High |
| Yu, Zhu et al | mortality (in hospital) | High |
| Yuan, Sun et al | mortality (in hospital) | High |
| Yuan, Yin et al. | mortality (in or out of hospital) | High |
| Zeng, Deng et al | severe covid-19 pneumonia | High |
| Zeng, Li et al. | progression to severe covid-19 | Unclear |
| Zeng, Li et al. | progression to severe covid-19 | Unclear |
| Zhang Xin, Wang Wei et al | other | High |
| Zhang, Guo et al | mortality (in or out of hospital) | High |
| Zhang, Guo et al | mortality (in or out of hospital) | High |
| Zhang, Guo et al | mortality (in or out of hospital) | High |
| Zhang, Liu et al | other (composite) | High |
| Zhang, Liu et al | other (composite) | High |
| Zhang, Liu et al. | covid-19 pneumonia | High |
| Zhang, Liu et al. | severe covid-19 | High |
| Zhang, Qin et al. | progression to severe covid-19 | High |
| Zhang, Shi et al | other (composite) | High |
| Zhang, Shi et al | other (composite) | High |
| Zhang, Shi et al | mortality (in hospital) | High |
| Zhang, Wu et al | severe covid-19 pneumonia | High |
| Zhang, Xie, et al. | other | High |
| Zhang, Zhang et al | progression to severe covid-19 | High |
| Zhang, Zhang et al | progression to severe covid-19 | High |
| Zhao, Chen et al | ICU admission | High |
| Zhao, Chen et al | mortality (in hospital) | High |
| Zhao, Wang et al | severe covid-19 | High |
| Zhao, Wei et al | covid-19 diagnosis | High |
| Zheng, Deng et al. | covid-19 diagnosis | High |
| Zheng, Xiao et al | other (composite) | High |
| Zheng, Xu et al. | length of hospital stay | High |
| Zheng, Zhu et al | progression to severe covid-19 | High |
| Zheng, Zhu et al | progression to severe covid-19 | High |
| Zhou, Chen et al. | covid-19 diagnosis | High |
| Zhou, He et al. Development and validation of a nomogram | severe covid-19 | High |
| Zhou, He et al. Exploiting an early warning nomogram | ICU admission | High |
| Zhou, Huang et al. | mortality (in hospital) | High |
| Zhou, Qin et al. | length of hospital stay | High |
| Zhou, Qin et al. | progression to severe covid-19 | High |
| Zhou, Qin et al. | length of hospital stay | High |
| Zhou, Qin et al. | progression to severe covid-19 | High |
| Zhou, Qin et al. | length of hospital stay | High |
| Zhou, Qin et al. | progression to severe covid-19 | High |
| Zhou, Qin et al. | length of hospital stay | High |
| Zhou, Qin et al. | progression to severe covid-19 | High |
| Zhou, Yang, et al. | severe covid-19 pneumonia | High |
| Zhu, Cai et al | severe covid-19 | High |
| Zhu, Ge, et al. | mortality (in or out of hospital) | High |
| Zou, Li et al | mortality (in hospital) | High |