Sutton's law and coronary risk factor reduction.

Abstract

Depending on the strength of the evidence for a causative role in coronary heart disease (CHD), coronary risk factors are viewed as established or “emerging.”1 The latter are further categorized as “probable” or “possible” etiologic factors. One of the most striking medical advances of the last century is confirmation that reduction of the established risk factors—cigarette smoking, dyslipidemia, and hypertension—markedly decreases cardiovascular mortality and morbidity.1 It is, therefore, paradoxical that a persistent disparity exists between evidence for the favorable effects of risk factor reduction and the inadequate application of these findings to patient care. This phenomenon is so prominent that it has gained recognition as the “knowledge-practice” gap.2, 3 A further concern is that in association with undertreatment of the major risk factors, physician interest in emerging, unproven factors is a continuing priority. This imbalance violates Sutton's time-honored quip, in response to why he robbed banks: “Because that's where the money is.” A more redeeming form of pragmatism in the clinical arena would be recognition that the major coronary risk factors are the chief causes of CHD and effective treatment yields remarkable benefits. This matter was recently addressed by Magnus4 in a forceful refutation of the common misconception that the major coronary risk factors account for 50% or less of the world's CHD. He cites numerous publications in which the “50% myth” is advanced. By utilizing rigorous epidemiologic data from large cohorts of men and women observed long term, Magnus conservatively estimates that 75% of CHD can be explained by the three major risk factors. If other important risk factors, such as diabetes, inactivity, and obesity are also considered, all but a small proportion of CHD can be explained without resorting to currently popular but unproven factors. Therefore, distraction by putative new risk factors may contribute to our current failure to fully act on available knowledge concerning the benefits of risk reduction. Numerous guidelines have been promulgated to support evidence-based prevention and management of cardiovascular disease. Their theoretical value—and for many clinicians—their daily utility, is real. However, with the multiple time-consuming burdens currently faced by physicians, some of these complex guidelines are not practical. On the other hand, the recently updated recommendations for secondary prevention of CHD of the American Heart Association/American College of Cardiology5 comprise a compact, practical (one-page) guideline to optimize management of patients with atherosclerotic vascular disease. There is more than enough evidence to pursue this approach to its full potential. As asserted by Magnus, “...the pursuit of new factors should not be at the expense of acting on what we already know.”4