2024 Revision of the level of evidence grading system for ESC clinical practice guideline recommendations I: therapy and prevention

Conclusive evidence usually from ≥2 adequately powered randomized controlled trials (RCTs) free from major bias, with substantial evidence against the play of chance when combined in a meta-analysis (e.g. P < .005 for superiority); additional criteria for non-inferiority, equivalence and harm

Suggestive evidence usually from ≥1 adequately powered RCT free from major bias, or a meta-analysis of such RCTs, with some evidence against the play of chance (e.g. P < .05 for superiority)

Limited evidence from ≥2 adequately powered non-randomised studies with careful control of major sources of bias or from a meta-analysis of small, underpowered RCTs

Preliminary evidence from non-randomised studies without careful control of major sources of bias, a single small, underpowered RCT, or expert consensus