Table 2. Critical appraisal skills program checklist for quality assessment of observational studies (CASP) (Long, French & Brooks, 2020).

NO.	Study authors	Critical appraisal of introduction 16.65%			Critical appraisal of methodology 26.64%										Critical appraisal of results and discussion 56.61%																	CASP score 100%
1	(Zhang et al., 2011) (China)	√	√	√	√	X	√	X	√	√	X	√	√	X	√	X	√	√	X	√	X	√	X	X	√	X	√	√	√	√	√	70 Strong Evidence
2	(El-Shenawy et al., 2012) (Saudi Arabia)	√	√	√	√	X	√	X	√	√	X	√	√	X	√	X	√	√	X	√	√	X	√	X	√	X	√	X	√	√	√	61.66 Moderate Evidence
3	(Lee et al., 2013) (Korea)	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	X	√	√	√	√	X	X	√	√	√	√	86.66 Strong Evidence
4	(Pietropaoli et al., 2013) (Italy)	√	√	√	√	X	√	X	√	√	X	√	√	X	√	X	√	√	X	√	X	√	X	X	√	X	√	X	√	√	√	65 Moderate Evidence
5	(Xie et al., 2014) (China)	√	√	√	√	X	√	X	√	√	X	√	√	X	√	√	√	√	X	√	X	√	X	X	√	X	√	√	√	√	√	71.66 Strong Evidence
6	(Niska et al., 2015) (Poland)	√	√	√	√	√	√	X	√	√	√	√	√	√	√	√	√	√	X	√	X	√	√	X	√	X	√	√	√	√	√	83.33 Strong Evidence
7	(Mariarosaria et al., 2017) (Italy)	√	√	√	√	X	√	X	√	√	X	√	√	X	√	X	√	√	X	√	√	X	√	X	√	X	√	X	√	√	√	63.33 Moderate Evidence
8	(Borys et al., 2018) (Poland)	√	√	√	√	√	√	X	√	√	√	√	√	X	√	√	√	√	X	√	X	√	√	√	√	√	X	X	√	√	√	77.66 Strong Evidence
9	(Hu et al., 2018) (China)	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	X	√	√	√	√	√	X	√	√	√	√	90 Strong Evidence
10	(Yu et al., 2018) (China)	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	X	√	√	√	√	X	X	√	√	√	√	86.66 Strong Evidence
11	(Shen et al., 2019) (China)	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	98.33 Strong Evidence
12	Mijiritsky et al., 2019 (Italy)	√	√	√	√	√	√	X	√	√	√	√	√	X	√	√	√	√	X	√	X	√	√	√	√	√	√	X	√	√	√	78.33 Strong Evidence
13	(Yang et al., 2020) (China)	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	X	√	√	√	√	√	X	√	√	√	√	88.33 Strong Evidence
14	(Huang et al., 2021) (China)	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	√	X	√	√	√	√	X	X	√	√	√	√	86.66 Strong Evidence

Notes.

√

Point awarded

X

Point not awarded