American College of Cardiology (ACC) and the American Heart Association (AHA) have jointly produced clinical practice guidelines since the 1980s. Because their guidelines are intended for use by a broad range of health providers, the ACC/AHA writing committees often include representatives of other organizations, including other groups specializing in the cardiovascular field, such as the American College of Chest Physicians, and other specialties such as the American Academy of Family Practice and the American College of Physicians. In seeking to develop consensus guidelines, the NHLBI’s National Cholesterol Education Program has also developed a partnership of multiple stakeholder groups, which in addition to physicians includes patient-focused groups, such as the American Diabetes Association and others.
Organizations that produce guidelines conduct their work and communicate their findings in different ways. Evidence-based guideline producers typically provide summary information about key findings including the quality of the individual studies included in the assessment, the quality of the overall body of evidence, and the strength of the recommendations. Each of these components can be depicted in a variety of ways by using letters, numbers, symbols, and words (Schünemann et al., 2003). For example, Table 5-2 highlights the grading scales that different organizations use to characterize the same cardiology interventions.
Although the overall quality of clinical practice guidelines has been improved by the efforts that have been made to grade the quality of evidence and the strength of recommendations, according to some the proliferation in the number of grading systems has undermined the value of the grading exercise (Guyatt et al., 2006a). As a result, many people have called for the development of a system that would standardize these grading systems and rating scales. The use of a common approach to grading the strength of recommendations is considered a mechanism that could facilitate the critical appraisal of a guideline development panel’s judgments and aid the interpretation of the benefits and risks of an intervention (Guyatt et al., 2006a; Schünemann et al., 2006). Standardization is likely to be difficult, though, because many organizations have invested considerable time and effort in developing unique rating systems and are reluctant to change (Guyatt et al., 2006b).
A number of national and international programs use or are developing standardized grading scales within their organizations, including the USPSTF, the United Kingdom’s NICE, and others (Schünemann et al., 2006). In addition, the major family medicine journals in the United States have created the Strength of Recommendation Taxonomy, which they be-