The effect of acarbose on insulin resistance in obese hypertensive subjects with normal glucose tolerance: a randomized controlled study.

Aim: Acarbose, a glucose oxidase inhibitor, delays the absorption of glucose thus reducing post-prandial blood glucose level, haemoglobin A1c (HbA1c) and insulin resistance in patients with diabetes mellitus and in subjects with impaired glucose tolerance. The effect of acarbose in subjects with normal glucose tolerance (NGT) has hitherto not been examined. The aim of the present study was to examine the effect of acarbose in obese hypertensive subjects with NGT.

Methods: A double-blinded, parallel group study was performed on 56 male subjects with hypertension, body mass index (BMI) 27-35 kg/m2, fasting blood glucose < or =6 mmol/l and a normal oral glucose tolerance test. Blood pressure, HbA1c, lipid profile and insulin resistance [homeostasis model assessment (HOMA) index] were determined initially and following 24 weeks of acarbose, 150 mg/day or placebo. The primary end point was the change in insulin resistance. Anti-hypertensive treatment and diet were kept constant during the study.

Results: Insulin resistance decreased in acarbose users but not on placebo. HOMA index declined from 5.36 +/- 1.7 to 4.10 +/- 1.6 (p=0.001) on acarbose, the corresponding values on placebo were 5.44 +/- 1.9 and 5.53 +/- 1.7. A decrease in serum triglyceride values (2.16 +/- 0.16 mmol/l to 1.76 +/- 0.15 mmol/l, p=0.02) took place on acarbose with no change on placebo. There was no change in BMI, low-density lipoprotein or high-density lipoprotein values in either group. Blood pressure declined equally in both the groups, probably due to better patient compliance.

Conclusions: Acarbose may reduce insulin resistance and triglycerides also in obese hypertensive subjects with normal glucose tolerance.