Clinical risk scores are not sufficient to define primary prevention treatment strategies among asymptomatic patients

The central principle of primary prevention is that treatment decisions must be carefully matched to accurate estimates of risk. The currently accepted method for determining coronary heart disease (CHD) risk among asymptomatic individuals is through calculation of the risk factor-based Framingham Risk Score (FRS).1 The FRS relies predominantly on age, sex, and to a lesser degree the traditional modifiable CHD risk factors (smoking, blood pressure, total cholesterol, high-density lipoprotein cholesterol, diabetes mellitus) to derive a statistical probability of developing a myocardial infarction or CHD-related death in the ensuing 10 years. Although the FRS has proven to be a useful tool, its overall predictive value in modern cohorts is modest (C-statistic, 0.70-0.75).2 Risk factor profiles widely overlap in those with and without CHD events, with the FRS failing to identify many truly high-risk individuals who are likely to benefit from preventive therapy. For example, 75% of younger patients presenting with ST-elevation myocardial infarction were considered low risk the day before their event.3 The majority of all CHD events continue to occur in patients considered either low or intermediate risk at baseline FRS assessment.