The lipoprotein profile differs during insulin treatment alone and combination therapy with insulin and sulphonylureas in patients with Type 2 diabetes mellitus

Summary Aims To study whether changes in endogenous insulin secretion at the same glycaemic control affect the plasma concentrations of lipoproteins in patients with Type 2 diabetes mellitus. Methods Fifteen patients, age 59 ± 2 years (mean ±sem), body weight 86.3 ± 3.0 kg, body mass index 29.6 ± 0.9 kg/m2 were treated with sulphonylurea and insulin in combination or with insulin alone in a randomized, double‐blind, crossover study. All patients were treated with a multiple daily injection regimen with the addition of glibenclamide 10.5 mg daily or placebo tablets. Results During combination therapy, the dose of insulin was 25% less (P < 0.002) and there was a 29% increase in plasma C‐peptide concentration (P = 0.01). Plasma levels of free insulin were not changed. Plasma levels of sex hormone‐binding globulin (SHBG) and insulin‐like growth factor‐binding protein (IGFBP)‐1 were lowered. There were no differences in the 24‐h blood glucose profiles or HbA1c (6.0 ± 0.2 vs. 6.3 ± 0.2%; P = 0.16). Body weight was similar. There was a significant decrease in plasma LDL cholesterol (3.04 ± 0.24 vs. 3.41 ± 0.21 mmol/l; P = 0.04), apolipoprotein A1 and of lipoprotein(a) but an increase i