The recent publication of the changes and current levels of evidence for the guidelines from the American College of Cardiology, American Heart Association, and the European Society of Cardiology once again indicates that the level of high-quality scientific data supporting the decision making process is limited.
Of the thousands of recommendations among the guidelines provided, level A data – which is supported by at least two randomized, controlled trials (RCT), arguably the gold standard for the proof of benefit of a treatment program – was available in only 8.5% of ACC/AHA recommendations and in 14.2% of ESC recommendations. The recent review covering guidelines published from 2008 to 2018 has changed very little since the previous review carried out on data collected between 1999 and 2014 (JAMA. 2019 Mar 19;321:1069-80). Admittedly, by the nature of their design, RCTs represent a very special subset of any disease process but they are the best we can do. The remainder of the guidelines is supported by nonrandomized data and consensus opinion of “experts.” The absence of randomized data in the rest of the guidelines creates an area of uncertainty between clinical practice and outcomes.
Guidelines have been with us for almost 30 years and have provided a near “cookbook recipe” for the treatment of almost the totality of cardiovascular care, both in the United States and Europe. There is little evidence that guideline dissemination results in a beneficial effect on cardiovascular care, instead reflecting the contemporary published research and informed opinion of our generation.
Despite the limitation of hard data based on RCTs, cardiovascular mortality has leveled off in the last few years. Although there are a number of areas that could be investigated with more focused and practical RCTs, there has been little enthusiasm by either the National Heart, Lung, and Blood Institute or the pharmaceutical or device industries to investigate existing cardiovascular drugs and/or devices to better elucidate nuanced therapy for subsets of heart disease that remain in the uncertain data areas. In fact, the current report shows that there has been little change in guidelines in the last 10 years. Most effort has been focused on new drug development and application.
Much of the advance in cardiovascular care and decrease in mortality is a result of the development of new drugs for the treatment of hypertension, management of hypercholesterolemia, and MI, together with coronary angiography and its interventional permutations of the previous 50 years. Those advances are now part of our knowledge base, our therapeutic DNA, and in the absence of some new scientific breakthrough, there is little to expect from future guideline development. Medical students and house officers are being taught as fact what we found as exciting new therapy just a few short years ago. Guidelines are now part of textbook knowledge and until new clinical outcome are reported, guidelines will probably serve a useful reference material but will not lead to much change in clinical care.
Even so, treating the patient in the clinic and in the hospital still requires the doctor to practice the “art” of medicine and to synthesize therapy based on the paucity of scientific data and quasi knowledge acquired over a generation.
The appreciation that much is unknown gives the doctor the humility required to be sensitive to patient needs and their symptoms and the aspiration for new, science-based data. This is still part of the excitement of being a doctor.
Dr. Goldstein, medical editor of Cardiology News, is professor of medicine at Wayne State University and division head emeritus of cardiovascular medicine at Henry Ford Hospital, both in Detroit. He is on data safety monitoring committees for the National Institutes of Health and several pharmaceutical companies.