Table 1

‚ÄÉRevised SIGN grading system: grades of recommendation

AAt least one meta-analysis, systematic review, or randomised controlled trial (RCT) rated as I++ and directly applicable to the target population; or a systematic review of RCTs or a body of evidence consisting principally of studies rated as I+ directly applicable to the target population and demonstrating overall consistency of results
BA body of evidence including studies rated as II++ directly applicable to the target population and demonstrating overall consistency of results; or extrapolated evidence from studies rated as I++ or I+
CA body of evidence including studies rated as II+ directly applicable to the target population and demonstrating overall consistency of results; or extrapolated evidence from studies rated as II++
DEvidence level III or IV; or extrapolated evidence from studies rated as II+