Until recently, the role of statin therapy in diabetic patients without clinical signs or symptoms of coronary heart disease had been inadequately defined. The Collaborative Atorvastatin Diabetes Study (CARDS) is a prospective, randomized, placebo-controlled trial designed to compare the effects of atorvastatin with placebo in preventing primary coronary events in diabetic patients. After a median of only 3.9 years (the study was terminated approximately 2 years early due to the magnitude of benefit attributable to atorvastatin therapy), risk for major cardiovascular events was decreased by 37%, acute coronary heart disease-related events were also reduced by 36%, coronary revascularizations by 31%, and stroke by 48%. Benefit emerged within 1 year of initiating therapy.