Table 1: Grade used in the recommendation.

Grade of recommendation	Clarity of risk/benefit	Quality of supporting evidence	Implications
1A. Strong recommendation, high quality evidence	Benefits clearly outweigh risk and burdens.	Consistent evidence from well performed randomized, controlled trials or overwhelming evidence of some other form.	Strong recommendation, can apply to most patients in most circumstances without reservation.
1B. Strong recommendation, moderate quality evidence	Benefits clearly outweigh risk and burdens.	Evidence from randomized, controlled trials with limitations or very strong evidence of some other research design.	Strong recommendation and applies to most patients.
1C. Strong recommendation, low quality evidence	Benefits appear to outweigh risk and burdens.	Evidence from observational studies, unsystematic clinical experience, or case reports.	Strong recommendation, but could change if new evidence appears.
2A. Weak recommendation, high quality evidence	Benefits closely balanced with risks and burdens.	Consistent evidence from well performed randomized, controlled trials or overwhelming evidence of some other form.	Weak recommendation, best action may differ depending on circumstances or patients or societal values.
2B. Weak recommendation, moderate quality evidence	Benefits closely balanced with risks and burdens.	Evidence from randomized, controlled trials with limitations or very strong evidence of some other research design.	Weak recommendation, alternative approaches likely to be better for some patients under some circumstances.
2C. Weak recommendation, low quality evidence	Uncertainty in the estimates of benefits, risks, and burdens; benefits may be closely balanced with risks and burdens.	Evidence from observational studies or case reports.	Very weak recommendation; other alternatives may be equally reasonable.