Effects of short‐term treatment with metformin on markers of endothelial function and inflammatory activity in type 2 diabetes mellitus: a randomized, placebo‐controlled trial

. Objectives. The UK Prospective Diabetes Study (UKPDS) showed that treatment with metformin decreases macrovascular morbidity and mortality independent of glycaemic control. We hypothesized that metformin may achieve this by improving endothelial function and chronic, low‐grade inflammation. Data on this issue are scarce and we therefore tested, in the setting of a randomized, placebo‐controlled trial, whether metformin can affect endothelial function and low‐grade inflammation. Design. The Hyperinsulinaemia the Outcome of its Metabolic Effects (HOME) trial is a double‐blind trial, in which all patients were randomized to receive either metformin or placebo in addition to insulin therapy. At the beginning and the end of a 16‐week treatment period fasting blood samples were drawn and a physical examination was carried out. Setting. The trial was conducted in the outpatient clinics of three nonacademic hospitals (Hoogeveen, Meppel and Coevorden; the Netherlands). Subjects. Patients were included if they were between 30 and 80 years of age; had received a diagnosis of diabetes after the age of 25; had never had an episode of ketoacidosis; and their blood glucose‐lowering treatment previously consisted of oral agents but now only consisted of either insulin (n = 345) or insulin and metformin (n = 45). We excluded pregnant women and women trying to become pregnant, patients with a Cockroft‐Gault‐estimated creatinine clearance