Table 1

‚ÄÉRevised SIGN grading system: grades of recommendation

AAt least one meta-analysis, systematic review, or RCT rated as 1++ and directly applicable to the target population; or
A systematic review of RCTs or a body of evidence consisting principally of studies rated as 1+ directly applicable to the target population and demonstrating overall consistency of results.
BA body of evidence including studies rated as 2++ directly applicable to the target population and demonstrating overall consistency of results; or
Extrapolated evidence from studies rated as 1++ or 1+.
CA body of evidence including studies rated as 2+ directly applicable to the target population and demonstrating overall consistency of results; or
Extrapolated evidence from studies rated as 2+.
DEvidence level 3 or 4; or
Extrapolated evidence from studies rated as 2+.