oronary heart disease (CHD) represents one of the main causes of death in the USA and Europe, 1 and is the second most frequent cause of death in Japan. 2 CHD risk increases remarkably with the accumulation of risk factors. [3][4][5] Data from some epidemiological studies and clinical trials have identified several risk factors for CHD 6,7 and some risk prediction scores for CHD were developed using risk factor analysis from these data. The Framingham risk model is a typical one. 8 However, it is well known that the estimated incidence of CHD by the Framingham prediction model is not consistent with the actual incidence in different populations. Therefore, different prediction scores have been developed in several countries. [9][10][11][12] In 2006, the Health Risk Evaluation Chart, 13 a risk chart corresponding to the Framingham CHD risk score, was developed based on the Nippon Data 80, 14 which used a 19-year follow-up study of data of the Japanese general population.
Circulation Journal Vol.72, October 2008Thus, despite the different risk prediction tools available in several countries, it remains unclear whether these tools accurately predict risk in patients with hypercholesterolemia treated by diet with or without a statin. Regarding risk prediction for the population receiving lipid-lowering pharmacotherapy, the CHD predicted value obtained from the Framingham risk model was compared with the observed CHD incidence in a substudy of WOSCOPS, 15 conducted to confirm the efficacy of pravastatin to prevent the first onset of ischemic heart disease. The observed incidence of CHD was similar to the predicted CHD risk using the Framingham risk model in the placebo group, whereas in the pravastatin group the observed CHD incidence was lower than the predicted CHD risk, indicating that the Framingham risk model does not accurately apply to patients receiving pravastatin. 16 The MEGA study is a large-scale clinical study conducted to evaluate the efficacy of pravastatin treatment to decrease the risk of cardiovascular events in patients with mild to moderate hypercholesterolemia without a past history of ischemic heart disease and/or stroke. 17,18 This report shows that 2 different 5-year CHD incidence risk prediction tools, a risk prediction score and chart, developed from the MEGA study data is accurate and efficient for clinical application.
MethodsThe Background A simple and practical risk prediction tool for coronary heart disease (CHD) to determine the specific risk level in each patient that fits the true clinical practice setting is needed and would be valuable in Japan.
Methods and ResultsA 5-year risk prediction score and chart for CHD based on the MEGA study data was developed in the present study. The MEGA risk prediction score and chart were constructed based on the coefficient of each risk factor. The risk factors included in these risk prediction tools were: treatment (diet, diet plus pravastatin), sex, age, baseline high-density lipoprotein-cholesterol, baseline low-density lipoprotein-cholesterol, ...