Acarbose vs. bedtime NPH insulin in the treatment of secondary failures to sulphonylurea-metformin therapy in type 2 diabetes mellitus

Abstract

Objective: To evaluate the efficacy of acarbose in the treatment of secondary failures to sulphonylurea-metformin therapy, its comparison against bedtime NPH insulin, and to measure the changes in postprandial metabolism resulting from both treatments.

Methods: One hundred type 2 diabetic patients in a secondary failure were included. The study begun with a run-in diet period of 6 weeks, in which an isocaloric diet was prescribed. Only subjects who continued hyperglycaemic were randomly assigned to placebo and acarbose (n = 17) or bedtime NPH insulin (n = 12). Acarbose (300 mg/day) or placebo were administered using a randomized, double blind, crossover design. Treatment periods of 3 months were separated by a 3-week washout period. Insulin was administered during 3 months. At the beginning and the end of each treatment period, an i.v. glucose tolerance test and a meal test were performed. Safety tests were done every 4 weeks.

Results: Acarbose resulted in a small but significant improvement in fasting plasma glucose (13.5 +/- 2.4 vs. 11.3 +/- 3.9 mmol/l, p = 0.05), HbA1c (11.1 +/- 3.4 vs. 10.3 +/- 2.5%, P = 0.3) and in a decreased plasma glucose during the meal test. Bedtime insulin significantly decreased fasting plasma glucose (13.1 +/- 2.9 vs. 8.2 +/- 2.3 mmol/l, p < 0.01), HbA1c (11.7 +/- 2.9 vs. 9.4 +/- 2.7%, p < 0.01) and plasma cholesterol. No change in insulin secretion resulted from insulin and acarbose treatment.

Conclusions: Acarbose decreases blood glucose in secondary failure to sulphonylurea-metformin therapy; however, the decrease is not enough to reach the desired metabolic control. Bedtime NPH insulin is, by far, a more effective alternative.