Abnormal platelet aggregation in chronic symptomatic diabetic peripheral neuropathy.

Both diabetic nephropathy and retinopathy result from microangiopathic processes although there is controversy as to whether this is true for neuropathy. Increased platelet aggregation has been reported in diabetics with nephropathy and retinopathy. The presence of increased platelet aggregation in diabetics with neuropathy could be due to the other coincident microvascular complications. We have, therefore, studied in vitro platelet aggregation in 10 diabetics with chronic symptomatic neuropathy but no other complications, 10 with neuropathy and severe retinopathy, 17 with retinopathy alone, and 23 diabetics with no complications. Increased platelet aggregation to adenosine diphosphate (ADP) and adrenaline was seen in diabetics with neuropathy alone (peak responses 85.0 +/- 5.5% and 82.9 +/- 6.2%, respectively) when compared with uncomplicated diabetics (peak response 74.9 +/- 10.1%, p less than 0.005, and 74.3 +/- 12.5%, p less than 0.01, respectively). The increased platelet aggregation in the patients with neuropathy alone was similar to that found in the diabetics with severe retinopathy. We conclude that increased platelet aggregation is associated with established microangiopathy and is also present in otherwise uncomplicated patients with neuropathy, and this may have pathogenic and therapeutic implications.