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The prevalence of diabetic retinopathy and the evaluation of its risk factors is poorly known in Italian population. Therefore, we have studied 894 diabetic outpatients (420 males, 474 females, 27.6% IDDs, 38.1% insulin-treated) in order to investigate the effect of clinical and metabolic characteristics on the frequency of diabetic retinopathy, classified into six different classes. In univariate analyses age, duration of disease, systolic and diastolic blood pressure, blood urea nitrogen, 24 hr proteinuria and fasting glycemia significantly correlated (p less than 0.001) with severity of retinopathy. The significance was confirmed in multivariate analysis for duration, age and systolic blood pressure (p less than 0.001). Stratification by type of diabetes showed that undefined onset of diabetes probably reduced in NID patients the power of duration as an associated factor of retinopathy. Worsening of this complication in three clinical classes of therapy (diet, oral and insulin-treatment) is evident too. Finally, our 11 variables in the step-wise multiple-regression analysis explain only 16.8% of diabetic retinopathy in all patients, but 36.6% in selected ID subjects.

The addition of vegetable fibres to the diabetic diet has been reported to ameliorate glycaemic and plasma lipid profiles, and Guar flour seems to obtain the best results. At its usual dose, Guar produces several gastro-intestinal side effects. A lower dose (4 + 4 g/day) was therefore employed in 10 non-insulin dependent diabetics (NIDD). The following parameters were measured at the end of treatment and after a control period: HbA1 levels, hepatic glucose production (3H-Glucose infusion), peripheral sensitivity to insulin and insulin secretion (hyperglycaemic clamp), and specific insulin binding to isolated monocytes. The ultracentrifugal plasma lipid pattern was also measured. No significant body weight change was recorded during the study. A significant glycaemic and insulinaemic decrease in the fasting state was observed after Guar, together with a significant decrease of HbA1 levels (from 8.5 +/- 0.4 to 7.9 +/- 0.4%, p less than 0.05) and amelioration of peripheral sensitivity to insulin (M/I = 14.3 +/- 6.6 versus 24.3 +/- 8.8, p less than 0.025; 50% increase of insulin binding to circulating monocytes) without significant variation of the fasting hepatic glucose production. Decreased B-cell stimulation by flattening post-prandial glycaemic peaks may be an explanation of the reduction of insulin resistance via down-regulation mechanism. As far as the lipid profile is concerned, a significant reduction in total and LDL cholesterol (p less than 0.05 and p less than 0.01) and an increase in HDL-phospholipids (p less than 0.05) were recorded after Guar. These results suggest that Guar in low doses is well accepted and can contribute to a better glycaemic and lipaemic control in NIDDM.