Table 1.

Evidence quality grades and strength of recommendations.

Items	Definition
Evidence quality
High	Confident enough that the true effect lies close to that of the estimate of the effect.
Moderate	Moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low	Confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect.
Very low	Very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect.
Strength of recommendation
Strong	Advantages of intervention significantly outweigh disadvantages or disadvantages of intervention significantly outweigh advantages.
Weak	Advantages of intervention may outweigh disadvantages or disadvantages of intervention may outweigh advantages or the relationship between advantages and disadvantages is not clear.