Design of the collaborative AtoRvastatin Diabetes Study (CARDS) in patients with Type 2 diabetes

Background There are few data on the role of lipid lowering in the primary prevention of coronary heart disease (CHD) in diabetic patients. This paper describes the design of a collaborative clinical trial between Diabetes UK, the NHS Research and Development Directorate and Pfizer UK, that addresses this question. Methods The Collaborative AtoRvastatin Diabetes Study (CARDS) is a multicentre, randomized, placebo-controlled, double-blind clinical trial of primary prevention of cardiovascular disease in patients with Type 2 diabetes. The primary objective is to investigate whether treatment with the hydroxymethylglutaryl coenzyme A reductase inhibitor, atorvastatin, reduces the incidence of major cardiovascular events. At entry patients have at least one other risk factor for CHD in addition to diabetes, namely current smoking, hypertension, retinopathy, or micro- or macroalbuminuria. At randomization patients have been selected for a serum low-density lipoprotein (LDL) cholesterol concentration less than or equal to 4.14 mmol/l (160 mg/dl) and triglycerides less than or equal to 6.78 mmol/l (600 mg/dl). Randomization was completed in June 2001. Patients will be followed until 304 primary endpoints have accrued (expected date early 2005). The trial includes 2838 men and women aged 40-75 years. This report describes the design and administration of the study and reviews the evidence to date of the effectiveness of lipid-lowering therapy in Type 2 diabetes. Conclusions The case for lipid-lowering therapy for the primary prevention of CHD in diabetes has not been demonstrated. CARDS will provide essential information on the extent of any benefits and adverse effects of lipid-lowering therapy in diabetic patients without prior CHD.