Plasma-lipids and glucose/insulin relationship in non-insulin-requiring diabetics with and without retinopathy

Serum-lipid concentrations and their relationship to blood-glucose and serum-insulin were examined in non-insulin-requiring diabetics, 62 with and 45 without retinopathy. The age, sex-body-weight, and duration of known diabetes was comparable in the two groups. All were treated by diet only or diet and oral hypoglycaemic agents. Patients with retinopathy had higher fasting serumtriglyceride and serum--cholesterol levels than those without. Compared with a non-diabetic population, significantly more diabetics with retinopathy had raised derum-lipids. The lipid concentrations did not correlate with body-weight, serum-thyroid-stimulating-hormone levels, renal involvement, or fasting blood-sugar. While the blood-sugar concentrations were similiar in the two groups the absolute insulin increment and the relative insulin response to a 50 g. oral glucose load were significantly lower in those with retinopathy than in those without. The impairment of insulin response correlated significantly with the frequency of hyperlipidaemia. It is suggested that insulin deficiency with secondary hyperlipidaemia is characteristic of diabetic patients with retinopathy.