Table 2.

Risk of bias in non-randomised studies -of interventions (ROBINS-I) tool

Author; Year	Bias due to confounding	Bias in selection of participants into the study	Bias due to missing data	Bias in measurement of outcomes	Bias in selection of the reported result	Overall bias
Gonzalez 2008 [7]	Moderate	Low	Low	Low	Moderate	Moderate
Mashour, 2008 [8]	Moderate	Low	Low	Low	Low	Low
Lavi2009[14]	Moderate	Low	Low	Low	Moderate	Moderate
Dargin 2013 [23]	Moderate	Low	Moderate	Low	Moderate	Moderate
Juvin 2003 [24]	Moderate	Low	Low	Low	Moderate	Moderate
Basaranoglu 2010 [25]	Moderate	Low	Low	Low	Moderate	Moderate
Ezri 2003 [26]	Moderate	Low	Low	Low	Moderate	Moderate
Heinrich 2013 [27]	Moderate	Low	Moderate	Low	Moderate	Moderate
Lee 2014 [28]	Moderate	Low	Low	Low	Moderate	Moderate
Voyagis 1998 [29]	Moderate	Low	Low	Low	Moderate	Moderate
Magalhães 2013 [30]	Moderate	Low	Low	Low	Moderate	Moderate
Turkay Aydogmus 2014 [31]	Moderate	Low	Low	Low	Moderate	Moderate
Aslani2012[32]	Moderate	Low	Low	Low	Moderate	Moderate
Combes2005[33]	Serious	Low	Low	Low	Moderate	Moderate
Yildiz 2010 [34]	Serious	Low	Low	Low	Moderate	Moderate
Lundstrøm 2009 [35]	Moderate	Low	Low	Low	Low	Low

All parameters were assessed for their risk by using a scale that classifies them as low, moderate, serious or critical