Table 1.

Previous systematic reviews on the application of AI for COVID-19 research.

Author, publication year	Number of articles	Objective	Comparison of information provided in previous vs. those provide in this review
Saleem et al., 2022 (7)	57	To highlight the latest developments in analyzing the COVID-19 data using machine learning and deep learning algorithms.	Articles with the following outcomes ✓Hospitalization ✓Mortality	Data-related aspects ✓Type of data ✓Country ✓Single/multi-country data sources x Type of covariates x Primary vs. secondary data	AI models-related aspects ✓Model ✓Model's performance ✓External validation x Internal validation x Type of filtering/prioritization x Supervised/not supervised x Calibration x Bias according to the prediction model risk of bias assessment tool	Epidemiological aspects x Nationwide/sampled population x Risk factors for mortality x Risk factors for hospitalization x Disease risk score for severe COVID-19 disease (death or hospitalization)
Napolitano et al., 2022 (8)	17 269	To identify the application of machine learning methods on COVID-19.	Articles with the following outcomes ✓Hospitalization ✓Mortality	Data-related aspects x Type of data x Country x Single/multi-country data sources ✓Type of covariates x Primary vs. secondary data	AI models-related aspects ✓Model ✓Model's performance x External validation x Internal validation x Type of filtering/prioritization x Supervised/not supervised x Calibration x Bias according	Epidemiological aspects x Nationwide/sampled population ✓Risk factors for mortality ✓Risk factors for hospitalization x Disease risk score for severe COVID-19 disease (death or hospitalization)
Lyu et al., 2022 (9)	19	To analyze the papers that used artificial intelligence (AI) models to forecast COVID-19 outcomes	Articles with the following outcomes ✓Hospitalization ✓Mortality	Data-related aspects x Type of data ✓Country x Single/multi-country data sources x Type of covariates x Primary vs. secondary data	AI models-related aspects ✓Model ✓Model's performance x External validation x Internal validation x Type of filtering/prioritization x Supervised/not supervised x Calibration x Bias according to the prediction model risk of bias assessment tool	Epidemiological aspects x Nationwide/sampled population x Risk factors for mortality x Risk factors for hospitalization x Disease risk score for severe COVID-19 disease (death or hospitalization)
Bottino et al., 2021 (10)	24	To look into the studies that implemented machine learning, including deep learning, methods in COVID mortality prediction	Articles with the following outcomes x Hospitalization ✓Mortality	Data-related aspects ✓Type of data ✓Country ✓Single/multi-country data sources ✓Type of covariates Primary vs. secondary data	AI models-related aspects ✓Model ✓Model's performance ✓External validation ✓Internal validation ✓Type of filtering/prioritization ✓Supervised/not supervised x Calibration x Bias according to the prediction model risk of bias assessment tool	Epidemiological aspects x Nationwide/sampled population ✓Risk factors for mortality x Risk factors for hospitalization x Disease risk score for severe COVID-19 disease (death or hospitalization)
Guo et al., 2021 (11)	794	To summarize how artificial intelligence (AI) is being applied in COVID-19 research and determine whether these AI applications integrated heterogeneous data from different sources for modeling.	Articles with the following outcomes ✓Hospitalization ✓Mortality	Data-related aspects ✓Type of data ✓Country ✓Single/multi-country data sources ✓Type of covariates x Primary vs. secondary data	AI models-related aspects ✓Model x Model's performance x External validation x Internal validation x Type of filtering/prioritization x Supervised/not supervised x Calibration x Bias according to the prediction model risk of bias assessment tool	Epidemiological aspects x Nationwide/sampled population x Risk factors for mortality x Risk factors for hospitalization x Disease risk score for severe COVID-19 disease (death or hospitalization)
Shi et al., 2021 (12)	27	To assess the potential predictors of mortality in patients with COVID-19.	Articles with the following outcomes x Hospitalization ✓Mortality	Data-related aspects ✓Type of data ✓Country x Single/multi-country data sources ✓Type of covariates x Primary vs. secondary data	AI models-related aspects ✓Model ✓Model's performance x External validation x Internal validation x Type of filtering/prioritization x Supervised/not supervised x Calibration xBias according to the prediction model risk of bias assessment tool	Epidemiological aspects x Nationwide/sampled population ✓Risk factors for mortality x Risk factors for hospitalization x Disease risk score for severe COVID-19 disease (death or hospitalization)
Syed et al., 2021 (13)	8	To identify the deep learning techniques that have been applied to predict hospital mortality in COVID-19 patients.	Articles with the following outcomes x Hospitalization ✓Mortality	Data-related aspects ✓Type of data x Country x Single/multi-country data sources ✓Type of covariates x Primary vs. secondary data	AI models-related aspects ✓Model ✓Model's performance x External validation x Internal validation x Type of filtering/prioritization x Supervised/not supervised x Calibration x Bias according to the prediction model risk of bias assessment tool	Epidemiological aspects x Nationwide/sampled population x Risk factors for mortality x Risk factors for hospitalization x Disease risk score for severe COVID-19 disease (death or hospitalization)
Alballa et al., 2021 (14)	52	To focus on the potential of ML for two main applications: diagnosis of COVID-19 and prediction of mortality risk and severity, using readily available clinical and laboratory data.	Articles with the following outcomes x Hospitalization ✓Mortality	Data-related aspects ✓Type of data x Country x Single/multi-country data sources ✓Type of covariates x Primary vs. secondary data	AI models-related aspects ✓Model ✓Model's performance ✓External validation ✓Internal validation ✓Type of filtering/prioritization ✓Supervised/not supervised x Calibration x Bias according to the prediction model risk of bias assessment tool	Epidemiological aspects x Nationwide/sampled population ✓Risk factors for mortality x Risk factors for hospitalization ✓Disease risk score for severe COVID-19 disease (death or hospitalization)