Key Points
Table 1. Recommendation Grading
Study Ratings
1
I++ High-quality meta-analyses, systematic reviews of randomized
controlled trials (RCTs), or RCTs with a very low risk of bias
I+ Well-conducted meta-analyses, systematic reviews of RCTs, or RCTs
with a low risk of bias
I- Meta-analyses, systematic reviews of RCTs, or RCTs with a high risk
of bias
II++ High-quality systematic reviews of case-control or cohort studies
High-quality case-control or cohort studies with a very low risk of
confounding or bias and a high probability that the relationship is
causal
II+ Well-conducted case-control or cohort studies with a low risk of
confounding or bias and a moderate probability that the relationship
is causal
II- Case-control or cohort studies with a high risk of confounding or
bias and a significant risk that the relationship is not causal
III Nonanalytic studies (e.g., case reports, case series)
Evidence Ratings
2
G - Good quality Further research is very unlikely to change our confidence in the
estimate of effect
M - Moderate
quality
Further research is likely to have an important impact on our
confidence in the estimate of effect and may change the estimate
In - Insufficient
quality
Further research is very likely to have an important impact on
our confidence in the estimate of effect and is likely to change the
estimate
Any estimate of effect is very uncertain
Recommendation Ratings
3
S - Strong
recommendation
Used when the desirable effects of an intervention clearly outweigh
the undesirable effects or clearly do not
D - Discretionary
recommendation
Used when the trade-offs are less certain—either because of low-
quality evidence or because evidence suggests that desirable and
undesirable effects are closely balanced
1. To rate individual studies, a scale based on Scottish Intercollegiate Guideline
Network (SIGN) is used.
2. The body of evidence quality ratings is defined by Grading of Recommendations
Assessment, Development and Evaluation (GRADE). GRADE is a systematic
approach to grading the strength of the total body of evidence that is available to
support recommendations on a specific clinical management issue.
3. Key recommendations for care are defined by GRADE.
