To the Editor: In their study, Dr Tricoci and colleagues1 pointed out that less than one-fifth of recommendations advocating a particular procedure or treatment in ACC/AHA practice guidelines were based on level A evidence. However, in using the ACC/AHA evidence grading schema to judge the quality of evidence underpinning guideline recommendations, I believe they have overestimated the strength of this evidence base. For example, under the ACC/AHA schema RCTs or meta-analyses are deemed to be level A evidence (or at worst level B if there is only a single RCT or the RCTs are small) irrespective of study conduct, end points evaluated (surrogate outcomes vs patient-centered outcomes), or the applicability of that RCT to the clinical scenario for which the recommendation is being made.
McAlister FA. Clinical Practice Guidelines and Scientific Evidence. JAMA. 2009;302(2):142-147. doi:10.1001/jama.2009.909