Objective: To evaluate the long-term efficacy of acarbose, an alpha-glucosidase inhibitor, in improving glycemic control in patients with non-insulin-dependent diabetes mellitus.
Design: A 1-year, multicenter, randomized, double-blind, placebo-controlled study.
Setting: Seven university-affiliated, community-based, tertiary care diabetes clinics.
Patients: 354 patients with non-insulin-dependent diabetes mellitus were recruited; 77 were being treated with diet alone, 83 with diet and metformin, 103 with diet and sulfonylurea, and 91 with diet and insulin. Patients in each treatment group were randomly assigned to either acarbose or placebo for 1 year. Eighty-seven percent of patients receiving acarbose and 92% of those receiving placebo were included in the efficacy analysis (n = 316).
Measurements: At baseline and at 3-month intervals, levels of hemoglobin A1c (HbA1c), fasting and postprandial plasma glucose, fasting and postprandial serum C-peptide, and fasting serum lipids were measured.
Results: Compared with placebo, acarbose treatment caused a significant decrease in the mean postprandial plasma glucose peak (90 minutes) in all four groups (19.0 +/- 0.4 mmol/L to 15.5 +/- 0.4 mmol/L; P < 0.001). Analysis of the postprandial plasma glucose incremental area under the curve showed that the change from baseline to the end of the treatment period differed for placebo and acarbose recipients by 4.73 mmol.h/L in the diet alone group (P < 0.001), 2.06 mmol.h/L in the metformin group (P = 0.01), 2.65 mmol.h/L in the sulfonylurea group (P < 0.001), and 3.13 mmol.h/L in the insulin group (P = 0.001). Corresponding decreases in HbA1c levels occurred; these were 0.9% in the diet alone group (P = 0.005), 0.8% in the metformin group (P = 0.011), 0.9% in the sulfonylurea group (P = 0.002), and 0.4% in the insulin group (P = 0.077). Acarbose did not significantly affect mean serum C-peptide or mean serum lipid levels.
Conclusions: Acarbose improved long-term glycemic control in patients with non-insulin-dependent diabetes mellitus regardless of concomitant antidiabetic medication.