Effect of oral hypoglycaemic drugs on glucose tolerance and insulin secretion in borderline diabetic patients

Abstract

A double blind controlled clinical trial was undertaken to test the effectiveness of oral hypoglycaemic drugs in improving blood glucose and plasma insulin levels of borderline diabetic patients. Between 1969 and 1971, 120 men aged 25 to 55 with borderline impairment of glucose tolerance according to standard criteria at 2 successive oral glucose tolerance tests entered the study. They were randomized into 4 groups according to treatment: dimethylbiguanide + glibenclamide (n=29), placebo B + glibenclamide (n=28), placebo S + dimethylbiguanide (n=30), placebo B + S (n= 33). In each group drugs were taken twice a day before breakfast and lunch at a total dosage of 1.7 g/ day dimethylbiguanide and/or 4 mg/day glibenclamide. Treatment was stopped after 2 years. Patients returned 2 months after entry into the trial, then every 4 months for 2 years. Treatment was continued up to each oral glucose tolerance test except before the last test (drugs stopped 15 days before). 29 patients weighed 20% or more over their ideal body weight and 23 between 10% and 20%. After a dietary survey, these men were subjected to a total colorie restricted diet according to their excess weight. Results indicate that during the 2 years of treatment, no significant lasting effect of the biguanide on blood glucose and plasma insulin levels was detectable. During the oral glucose tolerance test at 14 months in the groups receiving sulphonylurea a significant decrease of blood glucose levels was observed at 0, 180 and 240 min. Glibenclamide had no effect on weight reduction while biguanide administration was accompanied by a significant weight reduction. © 1978 Springer-Verlag.