Table 1 Grading standard for the evidence evaluation and recommendations in the current consensus [1,2,3,4]

Grading for evidence Evaluation

Grading standard for evidence evaluation

 Grade A

Randomized controlled clinical trials or meta-analyses based on such trials using proper methods.

 Grade B

Randomized controlled clinical trials, partially randomized controlled clinical trials, or meta-analyses based on such trials using methods with some insufficiencies.

 Grade C

Retrospective case studies or meta-analyses based on such studies.

 Grade D

Non-controlled studies (such as case reports), expert opinions, or evidence from basic medical research.

Grading for recommendations

Grading standard for recommendations

 Type I

A medical measure is proven and/or commonly agreed upon to be beneficial, useful, and effective.

 Type II

The effectiveness of a medical measure is still controversial.

  IIa

The evidence and/or perspective tends to be useful and effective.

  IIb

The evidence and/or perspective has not been proven useful and effective.

 Type III

A medical measure is proven and/or commonly agreed upon to be ineffective, may be harmful in some cases, and hence is not recommended.