Table 2.

Newcastle–Ottawa Scale quality assessment of included studies.

	Selection of participants	Comparability of study groups	Assessment of outcome/ ascertainment of exposure	Total score*
Talizin et al.18	<>	<>	<>	7
Ruiz-Castilla et al.7	<>	<>	<>	7
Dalfino et al.19	<>	<>	<>	8
Mazzeffi et al.1	<>	<>	<>	7
Demarchi et al.17	<>	<>	<>	7
Tyagi et al.14	<>	<>	<>	7

*Studies with 7 to 9 stars were deemed to be of high quality.