The Incremental Decrease in End Points through Aggressive Lipid Lowering (IDEAL) study is an investigator-initiated trial designed to determine whether additional clinical benefit might be gained through a strategy that decreases levels of low-density lipoprotein cholesterol levels better than those currently achieved with established statin therapy in patients who have coronary heart disease. IDEAL is a multicenter prospective, randomized, open-label, blinded, end point classification study. Patients who had myocardial infarction were randomized to prescription treatment with 80 mg/day of atorvastatin or 20 mg/day of simvastatin (the dose was increased to 40 mg/day at week 24 in those patients whose plasma total cholesterol remained >5.0 mmol/L, or 190 mg/dl, or whose low-density lipoprotein cholesterol remained >3.0 mmol/L, or 115 mg/dl). The primary clinical outcome variable is the time to initial occurrence of a major coronary event, which is defined as nonfatal acute myocardial infarction, coronary death, or resuscitated cardiac arrest. The study is designed to have a power of 90% to detect a relative decrease of 20% in the atorvastatin-group compared with the simvastatin-group in the number of major events caused by coronary heart disease over approximately 5.5 years. The 8,888 randomized patients had the following characteristics: mean age 61.7 +/- 9.5 years, 19.1% women (mean age 64.0 +/- 9.5 years), baseline total cholesterol 5.1 +/- 1.0 mmol/L (197 mg/dl), low-density lipoprotein cholesterol 3.2 +/- 0.9 mmol/L (124 mg/dl), and high-density lipoprotein cholesterol 1.2 +/- 0.3 mmol/L (46 mg/dl). Drug treatment before randomization consisted of statins in 77% of patients, aspirin in 78.9%, beta blockers in 75.1%, and angiotensin-converting enzyme inhibitors in 30%.