Six trials—British Medical Doctors (BMD) (11), Physicians' Health Study (PHS) (12), Thrombosis Prevention Trial (TPT) (13), Hypertension Optimal Treatment (HOT) (14), Primary Prevention Project (PPP) (15- 16), and Women's Health Study (WHS) (17)—were population-based and did not focus specifically on patients with diabetes. The percentage of patients with diabetes in these studies ranged from 1% to 2% in TPT, BMD, and PHS to 22% in PPP. Two recent trials, the Japanese Prevention of Atherosclerosis with aspirin for Diabetes (JPAD) (9) and the Prevention of Progression of Arterial Disease and Diabetes (POPADAD) (10), and one older trial, the Early Treatment of Diabetic Retinopathy Study (ETDRS) (18), enrolled only patients with diabetes. The available trials (except ETDRS) included mainly or exclusively patients with type 2 diabetes. ETDRS enrolled patients with both type 1 and type 2 diabetes (31% type 1, 31% type 2, and 38% unclassified).