Clinical Practice Guidelines and Scientific Evidence—Reply

In Reply: Dr Norris raises concerns about the process of guideline writing and development by the ACC/AHA. Our study focused on understanding the evolution of classes of recommendation to their present state and, more importantly, the extent to which the various levels of evidence were present within each class of recommendation. In our review, we found nothing to suggest that the ACC/AHA evaluation of evidence results in an inaccurate assessment of the existing evidence base, although this was not a primary objective of our study and was not systematically reviewed. We judged the language used for classes of recommendation and levels of evidence to be appropriate. Given the evolution of changes in the classes of recommendation and levels of evidence ratings of the ACC/AHA, it is our conclusion that the need for recommendations is increasing at a rate much greater than the available evidence base. This situation must be addressed to comply with the request of the Institute of Medicine and others for broad use of evidence-based medicine in patient care.