Table 3.

Newcastle Ottawa Scale (NOS) quality assessment of final article pool.

Trial, year	Study design	Newcastle ottawa scale
		Selection	Comparability	Exposure	Total scores
Porter et al. (11)	Retr	1	2	2	5
Mathiesen et al. (9)	Retr	2	3	2	7
Lunsford et al. (23)	Retr	1	2	2	5
Kida et al. (22)	Retr	2	2	3	7
Frischer et al. (20)	Retr	3	3	3	9
Haciyakupoglu et al. (21)	Retr	3	2	3	8

Retr, retrospective; Prosp, prospective.