Large Scale Cohort Study of the Relationship Between Serum Cholesterol Concentration and Coronary Events With Low-Dose Simvastatin Therapy in Japanese Patients With Hypercholesterolemia: Primary Prevention Cohort Study of the Japan Lipid Intervention Trial (J-LIT)

Hyperlipidemia is a well-established risk factor for primary coronary heart disease (CHD). Although simvastatin is known to lower serum lipid concentrations, the protective effect of such lipid-lowering therapy against primary CHD has not been established in Japanese patients with hypercholesterolemia. The Japan Lipid Intervention Trial was a 6-year, nationwide cohort study of 47,294 patients treated with open-labeled simvastatin (5-10 mg/day) and monitored by physicians under standard clinical conditions. The aim of the study was to determine the relationship between the occurrence of CHD and the serum lipid concentrations during low-dose simvastatin treatment. Simvastatin reduced serum concentrations of total cholesterol (TC), low-density lipoprotein- cholesterol (LDL-C) and triglyceride (TG), by 18.4%, 26.8% and 16.1% on average, respectively, during the treatment period. The risk of coronary events was higher when the average TC concentration was ≥240 mg/dl and the average LDL-C concentration was ≥160 mg/dl. The incidence of coronary events increased in the patients with TG concentration ≥300 mg/dl compared with patients with TG concentration