Table 2.

Grading of the Systematic Reviews and Meta-Analyses Based on AMSTAR 2 Criteria and Its Inference on Confidence of the Results of the Review.

Grading	Criteria	Inference
High	No or one noncritical 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 noncritical weaknessa	The systematic review 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 noncritical 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 noncritical 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

^a Multiple noncritical weaknesses may diminish confidence in the review and it may be appropriate to move the overall appraisal down from moderate to low confidence.