Table 1. GRADE grading standards.

Category	Definition	Notes
Grade of recommendation	A (strong recommendation)	Recommendations, for or against a particular management approach, are usually applicable to most patients
		Benefits clearly outweigh the risk and burdens, or vice versa
	B (weak recommendations)	Recommendations, for or against a particular management approach, may be conditional upon patients’ conditions and preferences
		The relationship between benefits and risks/burdens is more balanced or uncertain
	C (no recommendation)	There is insufficient evidence to recommend for or against a particular management approach
Level of evidence	A (high quality)	Evidence at a low risk of bias (e.g., consistent results from high-quality randomized trials) that can be applied directly to recommendations
	B (intermediate quality)	Study limitations, inconsistent results, and indirect evidence
	C (low quality)	Case analysis or nonsystematic clinical observations, with inadequate evidence

GRADE, Grading of Recommendations Assessment, Development and Evaluation.