Metabolic effects of clofibrate in insulin-dependent ketosis-prone diabetic man

Double-blind placebo-controlled study of the effects of bezafibrate on blood lipids, lipoproteins, and fibrinogen in hyperlipidaemic type 1 diabetes mellitus

The effects of bezafibrate 400 mg day-1 or placebo administered for 3 months, were compared in 36 patients with stable Type 1 diabetes and hypercholesterolaemia and/or hypertriglyceridaemia. Baseline characteristics of the 17 bezafibrate- and 19 placebo-treated patients were comparable in most respects with the exception of concentrations of fasting serum triglycerides and blood glucose which were lower (NS) and plasma fibrinogen which were higher (p less than 0.05), in those later treated with bezafibrate. Serum cholesterol concentrations decreased after 3 months bezafibrate treatment (from 7.1(0.2) (SE) to 6.3 (0.3) mmol l-1, p less than 0.05), predominantly due to a reduction in low density lipoprotein (LDL) cholesterol (from 4.8(0.3) to 4.2(0.3) mmol l-1, p less than 0.05). Over the same period bezafibrate reduced serum triglycerides from 1.78 (95% Cl 1.23-2.57) to 1.26(1.02-2.09) mmol l-1 (p less than 0.05), and plasma fibrinogen from 4.1(0.2) to 2.9(0.2) g l-1, p less than 0.001. Serum apolipoprotein B and apolipoprotein (a) showed no statistically significant changes. Overall there was no change in high density lipoprotein (HDL) cholesterol. However, in patients who were initially hypertriglyceridaemic there was significant increase in the cholesterol content of HDL and the HDL2-cholesterol subfraction (both p less than 0.05). After 3 months treatment with bezafibrate, fasting blood glucose levels were reduced from 8.5(1.1) to 6.4(0.7) mmol l-1, p less than 0.05, without any change in glycosylated haemoglobin (9.2(0.4) to 9.1(0.5)%).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of bezafibrate on insulin secretion and peripheral insulin sensitivity in hyperlipidemic patients with and without diabetes

Although it has been reported that bezafibrate influences carbohydrate metabolism, this possibility has never been properly evaluated in a controlled clinical trial. In this study we attempted to evaluate the effects of bezafibrate on plasma lipoproteins, glucose tolerance, insulin secretion and peripheral insulin sensitivity in a group of hypertriglyceridemic patients with and without diabetes. Sixteen hyperlipidemic patients (10 males and 6 females) participated in the study. Eight had type IIB and 8 type IV hyperlipoproteinemia; 6 of them also had non-insulin dependent diabetes mellitus. The study was performed according to a double blind, crossover design: after 1 month wash-out period in which patients were on diet alone, they underwent, in a random order, a period of placebo therapy and another period in which they received a single daily dose of a long-acting bezafibrate preparation (400 mg) administered in the evening. Each treatment lasted 2 months. Total plasma and VLDL triglyceride concentrations were consistently reduced by bezafibrate (-46%, P less than 0.001; and -50%, P less than 0.001). Total and VLDL-cholesterol were also reduced by bezafibrate. The effects of bezafibrate on lipoproteins were similar in diabetic and non-diabetic subjects. Bezafibrate treatment did not influence fasting blood glucose concentration, glucose tolerance, peripheral insulin sensitivity or insulin secretion. In conclusion, the results of this controlled trial clearly indicate that bezafibrate can be successfully employed to lower plasma lipid levels in patients with non-insulin dependent diabetes mellitus and hyperlipidemia.

Clofibrate enhances the affinity of insulin receptors in non-insulin dependent diabetes mellitus

Glucose-lowering mechanism by clofibrate was studied in non-insulin dependent diabetics managed with dietary therapy alone. Clofibrate 1500 mg was administered for 1 month to 15 patients, and 75 g oral glucose tolerance test and insulin tolerance test were carried out before and after 1 month of the treatment. Fasting plasma glucose values were decreased from 9.34 +/- 0.53 mmol/l to 7.58 +/- 0.33 mmol/l (P less than 0.01), and fasting insulin levels were decreased from 13.8 +/- 1.7 microunits/ml to 10.1 +/- 1.5 microunits/ml (P less than 0.05). However, insulinogenic index and sigma IRI/sigma glucose ratio during 75 g oral glucose tolerance test were not changed. Enhanced glucose fall in insulin tolerance test was also observed. As these results suggested the enhanced tissue sensitivity to insulin, we examined the insulin binding to erythrocytes before and at 3 months' treatment of clofibrate in 10 non-insulin dependent diabetics. Insulin bindings were increased from 3.41 +/- 0.17% to 4.11 +/- 0.20% in the presence of 1 ng/ml of native insulin (P less than 0.01). This increased binding was due to an increased affinity without a change in the number of insulin receptors. These results suggest that improved glucose tolerance by clofibrate might be derived from the enhanced tissue sensitivity to insulin, probably through an enhanced affinity of insulin receptors.

Clofibrate and diabetes control in patients treated with oral hypoglycaemic agents

1. Twenty-two maturity-onset type diabetics treated with oral hypoglycaemic agents entered a single-blind crossover study using placebo (periods A and C, 2 months each) and clofibrate (2 g/day; period B; 2 months). 2. In thirteen patients, under reasonably good control, clofibrate did not reduce fasting or post-prandial blood glucose, nor 24 h glycosuria; no improvement was noted in the M-value, an index of diabetes control. 3. In contrast, in nine patients, with poor diabetes control, clofibrate reduced 24 h glycosuria and significantly improved the M-value. 4. In all patients, clofibrate therapy was associated with a significant 19-23% reduction in plasma fibrinogen. 5. It is suggested that addition of clofibrate may be useful in maturity-onset diabetics not adequately controlled by diet combined with oral hypoglycaemic agents.