Comparison of acarbose and metformin in patients with Type 2 diabetes mellitus insufficiently controlled with diet and sulphonylureas: a randomized, placebo-controlled study

To compare the efficacy and safety of acarbose and metformin when added to sulphonylurea therapy in diabetic patients insufficiently controlled with sulphonylureas alone.A 12-week, single-centre, placebo-controlled study, with 89 patients randomized to receive acarbose (100 mg t.d.s.), metformin (850 mg b.d.) or placebo in addition to their sulphonylurea therapy. The study was double-blinded with respect to acarbose/placebo and single-blinded for metformin/ acarbose and metformin/placebo. Patients started a strict dietary regimen 1 week before receiving their first dose of acarbose, metformin or placebo. This regimen was individually adjusted to metabolic status and energy requirements.The primary endpoint, HbA1c, decreased from baseline in all three groups after 12 weeks. The decrease was greater in the two groups receiving active therapy compared with placebo (acarbose -2.3+/-0.32%; metformin -2.5+/-0.16%; placebo -1.3+/-0.34%). There was no significant difference between acarbose and metformin (P=0.65). Differences between both active therapies and placebo were statistically significant (acarbose P < or = 0.01; metformin P < or = 0.004). Reductions in body weight over the treatment period were seen in all three groups and were greatest in the acarbose group (median weight reduction: acarbose 3.5 kg; metformin, 1.0 kg; placebo 1.4 kg). There were no significant differences in the incidence of gastrointestinal side-effects between the three groups and all regimens were generally well tolerated.The results of the study demonstrate the equivalence of acarbose and metformin for improving metabolic control in patients insufficiently controlled with diet and sulphonylureas.