A randomized, blinded, multicenter clinical trial was performed comparing low- and high-dose simvastatin (40 and XO mg) with comparable doses of atorvastatin (20 and 40 mg) for effects on plasma concentrations of lipoproteins and apolipoprotein A-I over 12 weeks in 842 patients with elevated low-density lipoprotein cholesterol, The 2 agents reduced low-density lipoprotein cholesterol and triglycerides to a comparable degree, bur simvastatin raised high-density lipoprotein cholesterol and apolipoprotein A-I more than atorvastatin, suggesting differences in metabolic effects of the 2 agents on plasma lipids and lipoproteins.