Table 2.

Quality assessment using the AMSTAR-2.

		Cairns et al., 2014	Collins et al., 2019	Eime et al., 2013	Evans et al., 2017	Panza et al., 2020	Zuckerman et al., 2020
Item 1	PICO components	No	Yes	No	Yes	No	Yes
Item 2a	A priori protocol	No	No	No	No	Partial yes	No
Item 3	Study design	Yes	No	No	No	Yes	No
Item 4a	Search strategy	Partial yes	Partial yes	Partial yes	Partial yes	Partial yes	No
Item 5	Study selection	No	Yes	No	No	Yes	Yes
Item 6	Data extraction	Yes	No	No	Yes	Yes	Yes
Item 7a	Excluded studies	No	No	No	Yes	No	No
Item 8	Description of included studies	No	No	Partial yes	Partial yes	Yes	No
Item 9a	RoB assessment	No	Partial yes	Partial yes	No	No	Yes
Item 10	Reported funding	No	No	No	No	No	No
Item 11a	Meta-analyses methods	Yes	No	NAb	NAb	Yes	Yes
Item 12	Assess impact RoB on results meta-analysis	No	Yes	NAb	NAb	No	Yes
Item 13a	Account for RoB in interpreting/discussing of results	No	Yes	Yes	Yes	No	No
Item 14	Explanation of heterogeneity	No	Yes	Yes	Yes	Yes	Yes
Item 15a	Publication bias	Yes	Yes	NAb	NAb	Yes	No
Item 16	Conflict of interest	Yes	Yes	Yes	Yes	No	Yes
Overall score	Quality of the review	Critically low quality review	Critically low quality review	Moderate quality review	Critically low quality review	Critically low quality review	Critically low quality of review

^aIndicates a critical item on the AMSTAR-2; also shown in bold; _bNA indicates not applicable i.e. no meta-analysis conducted.

Rating was as follows: high quality of review: No or one non-critical weakness, Moderate quality of review: More than one non-critical weakness, Low quality of review: One critical flaw with or without non-critical weaknesses, Critically low quality of review: More than one critical flaw with our without non-critical weaknesses.

PICO = population, intervention/exposure, control/comparator, outcome; RoB = Risk of Bias.