Principles of prevention of cardiovascular disease.

Dear Sir The International Atherosclerosis Society (IAS) recently released harmonized guidelines for prevention of atheroscle-rotic disease through clinical management. 1 These guidelines integrate and harmonize existing guidelines for this purpose. Thanks to a large number of clinical trials, it is now possible to provide strong evidence-based guidelines for risk factor modification to prevent both recurrent atherosclerotic events (secondary prevention) and new onset events (primary prevention). Most guidelines in the cardio-vascular field are in agreement that intensive risk-factor intervention is both effica-cious and cost effective for secondary prevention. Moreover, recent guidelines have extended the concept of secondary prevention to include high-risk patients having several types of cardio-vascular disease (CVD) including established coronary heart disease (CHD), peripheral arterial disease, and stroke. In addition, many patients with diabetes have been shown to be at high risk, as are some persons with multiple risk factors. Both of these latter groups are candidates for intensive risk reduction as well. In the United States, a category of moderately high risk has further been identified as including patients with multiple risk factors who are not yet at high risk but who nonetheless will benefit from clinical risk intervention. Although most guidelines are in agreement that patients with established CVD are strong candidates for aggressive risk-reduction therapy, a major challenge in the field of CVD prevention is the identification of patients without CVD who are at high enough risk to justify clinical intervention, especially with drug therapy. Risk assessment for this purpose generally has employed multiple-risk-factor algorithms. Two risk-assessment tools widely used are the Framingham algorithm and the PROCAM algorithm. These two approaches give similar although not identical results. Both algorithms assess 10-year risk for " hard CHD " (myocardial infarction + CHD death). A new algorithm, called SCORE, was recently published. 2 This algorithm is designed to be used specifically in Europe, and it divides the European population into high-risk and low-risk regions. The same risk factors are used for both regions, but their relations to CVD are weighted differently. A critical feature of the SCORE algorithm is that it is based on prediction of total fatal CVD outcomes and not on total CVD events. The consequences for clinical management of this change in outcome for the risk algorithm must be examined. A critical question is whether the major purpose of primary prevention is to reduce the burden of atherosclerotic disease in society or to reduce CVD …