Converting the GRADE Level of Evidence to the AHA ECC Level of Evidence
GRADE Level of Evidence* Starting Point for AHA ECC Level of Evidence (to be adjusted as determined by the Writing Group)
High GRADE LOE/confidence in the estimates of effect Convert to AHA ECC LOE A for: High-quality evidence exists (well-designed, well- executed studies, each directly answers question, uses adequate randomization, blinding, allocation concealment, and is adequately powered, uses ITT analysis, with high follow-up rates). Evidence from >1 RCT, meta-analysis of high-quality RCTs, RCTs corroborated by high-quality registry studies.
Moderate GRADE LOE/confidence in the estimates of effect Convert to AHA ECC LOE B-R for: Moderate-quality evidence from RCTs or meta- analysis of moderate quality RCTs.
Low GRADE LOE/confidence in the estimates of effect (low or very low confidence is caused by limitations in risk of bias for included studies, inconsistency, imprecision, indirectness, and publication bias) Convert to AHA ECC LOE B-NR for: Moderate-quality evidence from well-designed and well-executed nonrandomized, observational, or registry studies or meta-analysis of same.
Very low GRADELOE/confidence in the estimate of effect (low or very low confidence is caused by limitations in risk of bias for included studies, inconsistency, imprecision, indirectness, and publication bias) Convert to AHA ECC LOE C-LD for: Randomized or nonrandomized observational or registry studies with limitations of design or execution (including but not limited to inadequate randomization, lack of blinding, inadequate power, outcomes of interest are not pre-specified, inadequate follow-up, or based on subgroup analysis) or meta-analyses with such limitations; or if physiologic or mechanistic studies in human subjects.
GRADE non-recommendation Convert to AHA ECC LOE C- EO for: Consensus of expert opinion based on clinical experience.
Clarification: The American Heart Association (AHA) classification is applied to the body of evidence supporting an individual recommendation, based largely on design and quality of studies addressing the clinical question (see above). Although the International Liaison Committee on Resuscitation (ILCOR) Grading of Recommendations Assessment, Development, and Evaluation (GRADE) recommendation attempts to consider factors such as resource allocation, the individual councils (eg, the AHA) are best able to identify the patients or subsets of patients, outcomes, and conditions that are most important to consider in the translation of science to guidelines.Disclaimer: The manuscript and its contents are confidential, intended for journal review purposes only, and not to be further disclosed.

Legend: * The GRADE process labels a body of evidence across outcomes based on the lowest Level of Evidence (LOE) for the most critical outcome. ECC indicates Emergency Cardiovascular Care; ITT, intention-to-treat; and RCT, randomized controlled trial.