Table 3.

Risk of bias assessment

Study ID	Selection	Comparability	Outcomes	NOS score
Dijos et al [16]	**	–	**	4
Bouleti et al [17]	**	*	**	5
Gajanana et al [18]	***	**	***	8
Agrawal et al [10]	***	**	***	8

(*) Asterisks denote the quality of each domain; NOS- Newcastle-Ottawa Scale. Numbers of stars in good quality: 3 or 4 in selection, 1 or 2 in comparability, and 2 or 3 in outcomes. Numbers of stars in fair quality: 2 in selection, 1 or 2 in comparability, and 2 or 3 in outcomes. Numbers of stars in poor quality: 0 or 1 in selection, 0 in comparability, and 0 or 1 in outcomes