Table 2.

Grading quality of evidence.

Level	Criteria
High-quality evidence (A) (Highly recommended)	One or more high-quality systematic review that are based on at least 2 high-quality primary studies with consistent results
Moderate-quality evidence (B) (Moderately recommended)	One or more systematic reviews of high or moderate quality •Based on at least 1 high-quality primary study •Based on at least 2 primary studies of moderate quality with consistent results
Low-quality evidence (C) (Uncertainty)	One or more systematic reviews of high or moderate quality •Based on primary studies of moderate quality •Based on inconsistent or conflicting results in the reviews •Based on inconsistent or conflicting results in primary studies
Very low-quality evidence (D) (No recommendation)	No high-quality systematic review identified or supports the intervention