ABSTRACT
OBJECTIVES: To measure the effect of metformin on the body composition, insulin resistance and sensitivity in subjects with risk factors for type 2 diabetes mellitus (type 2 DM). DESIGN: Placebo-controlled clinical trial. MATERIAL AND METHODS: Twenty-three subjects with risk factors for type 2 DM were randomly assigned to receive 850 mg of metformin or a placebo twice a day for 2 months. Before and after the treatment, the body mass index and waist/hip ratio were calculated, the body composition was measured through bioelectric impedance and the fasting levels of blood glucose, insulin, triglycerides and cholesterol were measured. The level of insulin resistance was calculated by the homeostatic model and the level of sensitivity by the quantitative insulin sensitivity check index method. The Wilcoxon rank test was used. RESULTS: Twenty-one subjects completed the study, 12 of the metformin group and nine of the placebo group. In the metformin group, there was a decrease in fat weight from 25.9 +/- 9.4 to 20.8 +/- 9.2 kg, p < 0.01, an increase in lean weight from 57.05 +/- 13.6 to 61.9 +/- 16.5 kg, p < 0.01, an increase in basal metabolism from 1735 +/- 413 to 1878 +/- 505 calories/day, p < 0.05 and an increase in body water, p < 0.05. There was no significant decrease in insulin resistance. In the placebo group, the blood glucose increased from 84.7 +/- 13 to 96.7 +/- 16 mg/dl, p < 0.05. There were no significant modifications in lipids. CONCLUSIONS: The administration of metformin for 2 months improves the parameters of body composition and insulin dynamics in subjects with risk factors for type 2 DM.
