Table 3.

Summary assessment of the risk of bias for 17 retrospective studies using the ROBIN-I tool

Author publication year	Bias due to confounding	Bias in the selection of participants into the study	Bias in the classification of interventions	Bias due to deviations from intended interventions	Bias due to missing data	Bias in measurement of outcomes	Bias in the selection of the reported result	Overall risk of bias
Bilimoria et al. (2009) [31]								Moderate risk of bias
Degnim et al. (2010) [32]								Serious risk of bias
Yi et al. (2010) [34]								Serious risk of bias
Gillanders et al. (2012) [35]								Serious risk of bias
Park et al. (2014) [37]								Moderate risk of bias
Snow et al. (2015) [38]								Serious risk of bias
Tvedskov et al. (2015) [39]								Serious risk of bias
Houvenaeghel et al. (2016) [40]								Moderate risk of bias
Youssef et al. (2016) [41]								Serious risk of bias
Lee et al. (2018) [44]								Serious risk of bias
Liu et al. (2018) [45]								Moderate risk of bias
Arisio et al. (2019) [46]								Serious risk of bias
Jung et al. (2019) [47]								Moderate risk of bias
Kim et al. (2019) [48]								Serious risk of bias
Jung et al. (2020) [49]								Moderate risk of bias
Kim et al. (2020) [50]								Moderate risk of bias
Sun et al. (2021) [51]								Serious risk of bias
Sanvido et al. (2021) [52]								Serious risk of bias
Gao et al. (2022) [54]								Moderate risk of bias
Houvenaeghel et al. (2022) [55]								Moderate risk of bias
Zhou et al. (2022) [57]								Moderate risk of bias

Notes: low risk of bias, moderate risk of bias, serious risk of bias, for critical risk of bias, no information