Platelet function in diabetic retinopathy: levels of beta-thromboglobulin and platelet factor 4.

Altered platelet function has been reported in diabetic patients. This article reports plasma levels of beta-thromboglobulin and platelet factor 4 as measures of in vivo platelet activity in diabetic and control groups. Both beta-thromboglobulin and platelet factor 4 were significantly higher in diabetics than in controls (p < 0.01). The levels observed were not significantly affected by age, sex, diabetes type or whether the diabetic had nonproliferative or proliferative retinopathy, but beta-thromboglobulin levels were significantly higher in diabetics of less than 10 years standing than in those who had suffered diabetes for over 20 years (p < 0.05).