Association between Lowering Low-Density Lipoprotein Cholesterol with Pravastatin and Primary Prevention of Cardiovascular Disease in Mild to Moderate Hypercholesterolemic Japanese

Aims: To evaluate the relationship between low-density lipoprotein cholesterol (LDL-C) change and reduction of cardiovascular disease in the Management of Elevated cholesterol in the primary prevention Group of Adult Japanese (MEGA) study. Methods: Patients in the diet plus pravastatin group were divided into tertiles by their on-treatment LDL-C level, and the hazard ratios (HRs) in each tertile were compared with the diet group at 5 years using the Cox proportional hazards model. In addition, the treatment groups were combined and divided into quintiles according to the on-treatment LDL-C level during follow-up, and the incidence of cardiovascular events was compared among the 5 groups. Results: In the tertiles of the diet plus pravastatin group, HR was lowest in the second tertile against the diet group (HR 0.57, p = 0.01) with on-treatment LDL-C range of 119.8-133.4 mg/dL. In the analysis of quintiles of the total population, a significant risk reduction of CVD was found in the fourth quintile (HR 0.48, p = 0.0015) with an on-treatment LDL-C range of 120.9-133.3 mg/dL, and in the fifth quintile (HR 0.64, p = 0.048) with an on-treatment LDL-C range of 56.7-120.8 mg/dL against tertile 1 with an on-treatment LDL-C range of 157.5-206.2 mg/dL. Conclusions: The usual Japanese dose of pravastatin therapy is sufficient in this low-risk patient population to reduce cardiovascular risk, with an achieved LDL-C level < 133.4 mg/dL. Further risk reduction was not found with an achieved LDL < 120 mg/dL.