Table 1.

Grades of evidence and strength of recommendation

Grade	Description
Quality of evidence
High (A)	Further research cannot change the reliability of the therapeutic efficacy evaluation results
Medium (B)	Further research might change the reliability of the therapeutic efficacy evaluation results and also the evaluation results
Low or extremely low (C)	Further research will likely change the reliability of the therapeutic efficacy evaluation results and will likely also change the evaluation results
Strength of recommendation
Strong (1)	Clearly indicates that the advantages of the intervention measures outweigh the disadvantages, or vice versa
Weak (2)	The advantages and disadvantages are indeterminate or the evidences, irrespective of the quality indicate that the advantages and disadvantages are equivalent