The effect of etidronate disodium (EHDP) on retinopathy in insulin-dependent diabetic patients

In a randomized double-blind study the effect of etidronate disodium (EHDP) on retinopathy, plasma inorganic phosphate and blood oxygen transport was assessed in 26 insulin-dependent diabetic patients. Following 6 months of EHDP administration, plasma inorganic phosphate had increased significantly (1.48 vs 1.14 mmol/l; P less than 0.01). Red cell, 2,3-diphosphoglycerate concentration (16.9 vs 15.1 mumol/g Hb; P less than 0.01) and the haemoglobin-oxygen affinity measured by pO2 at 50% oxygen saturation (P50) had also increased significantly (27.5 vs 26.3 mmHg; P less than 0.01). No changes had occurred in mean blood glucose and haemoglobin A1c concentrations, indicating a comparable degree of glucose regulation. Following 6 months of EHDP administration an association was found between improvement in retinopathy and the increase in plasma inorganic phosphate.