Table 1 American college of cardiology/American heart association recommendation system
Class (strength) of recommendation | |
|---|---|
Class I (Strong)—Benefit >>> Risk | |
Suggested phrases for writing recommendations: | |
Is recommended Is indicated/useful/effective/beneficial Should be performed/administered/other Comparative-Effectiveness Phrases | |
Treatment/strategy A is recommended/indicated in preference to treatment B Treatment A should be chosen over treatment B | |
Class IIa (Moderate)—Benefit >> Risk | |
Suggested phrases for writing recommendations: | |
Is reasonable Can be useful/effective/beneficial Should be performed/administered/other Comparative-Effectiveness Phrases | |
Treatment/strategy A is probably recommended/indicated in preference to treatment B It is reasonable to choose treatment A over treatment B | |
Class IIb (Weak)—Benefit ≥ Risk | |
Suggested phrases for writing recommendations: | |
May/might be reasonable May/might be considered Usefulness/effectiveness is unknown/unclear/uncertain or not well established | |
Class III: No Benefit (Moderate)—Benefit = Risk | |
Suggested phrases for writing recommendations: | |
Is not recommended Is not indicated/useful/effective/beneficial Should not be performed/administered/other | |
Class III: Harm (Strong)—Benefit < Risk | |
Suggested phrases for writing recommendations: | |
Potentially harmful Causes harm Associated with excess morbidity/mortality Should not be performed/administered/other | |
Level (Quality) of evidence | |
Level A | |
High-quality evidence from more than 1 RCT Meta-analyses of high-quality RCTs One or more RCTs corroborated by high-quality registry studies | |
Level B-R (randomized) | |
Moderate-quality evidence from 1 or more RCTs Meta-analyses of moderate-quality RCTs | |
Level B-NR (nonrandomized) | |
Moderate-quality evidence from 1 or more well-designed, well-executed nonrandomized studies, observational studies, or registry studies Meta-analyses of such studies | |
Level C-LD (limited data) | |
Randomized or nonrandomized observational or registry studies with limitations of design or execution Meta-analyses of such studies Physiological or mechanistic studies in human subjects | |
Level C-EO (expert opinion) | |
Consensus of expert opinion based on clinical experience |