Table 4.

Results of hierarchy of evidence

Author	Hierarchy level	Appraisal score	Quality category
Mwaka et al. (2014)[9]	Ib	15.16	High
Grimmer et al. (2002)[33]	Ib	15.16	High
Chansirinukor et al. (2001)[26]	IIa	7.16	Intermediate
Al Shahry et al. (2018)[22]	IIa	7.16	Intermediate
Akbar et al. (2019)[25]	Ib	7.16	Intermediate
Al-Khabbaz et al. (2008)[36]	IIa	8.16	Intermediate
Navuluri et al. (2006)[20]	IIa	10.16	Intermediate
Siambanes et al. (2004)[34]	IIa	8.16	Intermediate
Haselgrove et al. (2008)[21]	IIa	8.16	Intermediate
Aundhakaret al. (2015)[37]	IIa	10.16	Intermediate
Syazwan et al. (2011)[38]	IIb	8.16	Intermediate
Sharan et al. (2012)[23]	Ib	9.16	Intermediate
Grimmer et al. (2002)[33]	IIa	7.16	Intermediate
Spiteri et al. (2017)[35]	IIa	6.16	Intermediate