The effect of plasma glucose control by continuous subcutaneous insulin infusion or conventional therapy on retinal morphology and urinary albumin excretion

Abstract

The effect of plasma glucose control on retinal morphology, urinary albumin excretion and related haematological and lipid measurements was studied prospectively for 30 weeks in 17 patients with insulin-dependent diabetes mellitus. All had background diabetic retinopathy (BDR) and absence of albustix positive proteinuria: 9 were allocated to a continuous subcutaneous insulin infusion (CSII) group and 8 to a conventional therapy (CT) group. There was a sustained reduction (p less than 0.01) in haemoglobin A1 (HbA1) in the CSII group, but not in the CT group. Mean HbA1 over the 30 week study period was lower (p less than 0.05) in the CSII (8.9 +/- 0.3%) than the CT group (10.2 +/- 0.5%). Retinal morphology assessed by fluorescein angiography improved after 30 weeks in one patient in the CSII group, but in most patients it remained the same or deteriorated. The patient with the best plasma glucose control developed a small area of neovascularisation. Less deterioration in retinopathy was not related to better plasma glucose control. Urinary albumin excretion, plasma viscosity, plasma fibrinogen, red cell deformability and plasma lipids did not change in either the CSII or CT group. In the 7 patients selected from both groups who achieved the best control there was a reduction in urinary albumin and LDL cholesterol.