Agonist-induced platelet aggregation does not correlate with the varying severity of microangiopathy in patients with Type 2 diabetes mellitus

We investigated agonist-induced platelet aggregation in 23 age- and sex-matched control subjects and in 74 patients with type 2 diabetes mellitus. Platelet aggregation was measured by a particle counting method using light scattering (LS) and by a conventional light transmission method (LT) using epinephrine (Epi) and adenosine-5'-diphosphate (ADP) as agonists. Agonist-induced platelet aggregations measured by LS or LT did not show significant differences between control subjects and patients with type 2 diabetes mellitus as a whole. In addition, agonist-induced platelet aggregations by LS or IT did not show significant differenccs between control subjects and three diabetic patients subgroups with the varying severity of retinopathy, nephropathy or neuropathy. We recently reported that platelet aggregation in the absence of agonists (spontaneous aggregation) correlates well with the varying severity of microangiopathy. The results of the present study also support that spontaneous platelet aggregation measured by particle counting method using light scattering is more discriminative than agonist-induced platelet aggregation in relation to diabetic microangiopathy.