vel of Evidence
CLASS IIb
Benefit ≥ Risk
Additional studies with broad objectives needed;
additional registry data would be helpful
Procedure/Treatment
MAY BE CONSIDERED
CLASS III No Benefit
or CLASS III Harm
COR III:
No benefit
COR III:
Harm
Procedure/
Test
Treatment
Not Helpful No Proven
Benefit
Excess Cost
w/o Benefit
or Harmful
Harmful to
Patients
▪Recommendation's usefulness/efficacy less well
established
▪Recommendation that procedure or treatment
is not useful/effective and may be harmful
▪Greater conflicting evidence from multiple
randomized trails or meta-analyses
▪Sufficient evidence from multiple randomized
trials of meta-analyses
▪Recommendation's usefulness/efficacy less well
established
▪Recommendation that procedure or treatment
is not useful/effective and may be harmful
▪Greater conflicting evidence from single
randomized trial or nonrandomized studies
▪Evidence from single randomized trial or
nonrandomized studies
▪Recommendation's usefulness/efficacy less well
established
▪Recommendation that procedure or treatment
is not useful/effective and may be harmful
▪Only diverging expert opinion, case studies, or
standard of care
▪Only expert opinion, case studies, or standard
of care
may/might be considered
may/might be reasonable
usefulness/effectiveness is unknown/unclear/
uncertain or not well established
COR III: No benefit
is not recommended
is not indicated
should not be
performed/
administered/other
is not useful/beneficial/
effective
a
COR III: Harm
potentially harmful
causes harm
associated with excess
morbidity/mortality
should not be
performed/
administered/other
Data available from clinical trials or registries about the usefulness/efficacy in different subpopulations, such as
sex, age, history of diabetes, history of prior myocardial infarction, history of heart failure, and prior aspirin use.
For comparative effectiveness recommendations (Class I and IIa; Level of Evidence A and B only), studies that support
the use of comparator verbs should involve direct comparisons of the treatments or strategies being evaluated.
b
