Table 4.2

Clinical Practice Guideline Grading Models (ACCF/AHA Interpretation)

ACCF/AHAGRADEUSPTFNHLBIACP
Strength of RecommendationI (Strong)StrongAA-StrongStrong
Level of Evidence A High High High High
 B Moderate Moderate Moderate Moderate
 C Low Low Low Low
Strength of RecommendationIIa (Moderate)WeakBB-ModerateWeak
Level of Evidence A High High High High
 B Moderate Moderate Moderate Moderate
 C Low Low Low Low
Strength of RecommendationIIb (Weak)WeakCC-WeakWeak
Level of Evidence A High High High High
 B Moderate Moderate Moderate Moderate
 C Low Low Low Low
Strength of RecommendationIII: No Benefit OR Harm (Against)Strong or WeakDD-AgainstStrong or Weak
Level of Evidence A High High High High
 B Moderate Moderate Moderate Moderate
 C Low Low Low Low
Level of EvidenceI=insufficientE=expert opinionI=insufficient
N=no recommendation

ACCF indicates American College of Cardiology Foundation; ACP, American College of Physicians; AHA, American Heart Association; GRADE, Grading of Recommendations Assessment, Development, and Evaluation; NHLBI, National Heart, Lung, and Blood Institute; and USPTF, U.S. Preventive Services Task Force.

  • The ACCF/AHA level of evidence nomenclature identifies the type of evidence and correlates to a specific number, type and quality of studies, for example, randomized trials, observational data, or expert opinion. Other guideline developers incorporate the quality of evidence to imply a more defined qualitative and quantitative way of combining data from individual studies into an overall synthesis of the data defined as high, moderate, or low. Although determining the quality of studies informing recommendations within each level of evidence is inherent to the ACCF/ACC process, at this time the nomenclature used by the ACCF/AHA is not meant to be synonymous with overall quality of the body of evidence. It will be modified once an evidence grading tool is completed.