Published Monthly by the American College of Physicians

In view of the tendency toward vascular disease in diabetes mellitus, we studied platelet aggregation in 15 normal, 7 prediabetic, 12 latent, and 20 frankly diabetic subjects. Platelets from latent and frank diabetics showed increased platelet aggregation 4 minutes after adding adenosine 5'-diphosphate ( 6 0 % versus 2 9 % at 1.0 /zM), epinephrine (46 % versus 14 % at 0.25 ^M), and collagen ( 7 2 % versus 1 7 % at 0.25 ^g/ml). Three prediabetics had increased platelet aggregation. Platelet sensitivity to aggregating agents was most marked in frank diabetics, intermediate in latent diabetics, and least in prediabetics. Second-phase platelet aggregation was reversed with acetylsalicylic acid, intravenous tolbutamide, and oral glucose administration. We conclude that platelet aggregation may be increased early in diabetes mellitus and may be involve