Table 1 Quality assessment of systematic reviews according to AMSTAR-2 [29]

HIGH

No or one non-critical weakness

The systematic review provides an accurate and comprehensive summary of the results of the available studies that address the

question of interest

MODERATE

More than one non-critical weakness*

The systematic review has more than one

weakness but no critical flaws. It may provide an accurate summary of the results of the available studies that were included in the review

LOW

One critical flaw with or without non-critical weaknesses

The review has a critical

flaw and may not provide an accurate and comprehensive summary of the available

studies that address the question of interest

CRITICALLY LOW

More than one critical flaw with or without non-critical weaknesses

The review has more than one critical flaw and should not be relied on to provide an accurate and comprehensive summary of the available studies

Critical domains

    • Protocol registered before commencement of the review (item 2)

    • Adequacy of the literature search (item 4)

    • Justification for excluding individual studies (item 7)

    • Risk of bias from individual studies being included in the review (item 9)

    • Appropriateness of meta-analytical methods (item 11)

    • Consideration of risk of bias when interpreting the results of the review (item 15)

Non-critical weakness

    • PICO model (item 1)

    • Explain the selection for the inclusion (item 3)

    • Selection of studies in duplicate (item 5)

    • Data extraction in duplicate (item 6)

    • Describe the included studies (item 8)

    • Funding sources for the studies included in the review (item 10)

    • Potential impact of risk of bias in individual studies on outcomes (item 12)

    • Consideration of the risk of bias in individual studies when interpreting/discussing the results (item 13)

    • Heterogeneity observed (item 14)

    • Conflict of Interest (item 16)