Effect of metformin on cardiovascular risk factors in middle-aged Thai women with metabolic syndrome: A randomized placebo-controlled trial

Aim: To evaluate the effect of metformin on cardiovascular risk factors in middle-aged Thai women with metabolic syndrome that are in menopausal transition. Methods: This study was double-blind randomized placebo-controlled trial. Metabolic syndrome was diagnosed using American Heart Association and National Heart, Lung, and Blood Institute criteria. After taking metformin 1700 mg/day for 6 months, cardiovascular risk factors were evaluated at baseline and month-6; the values of which were used to calculate delta (Δ, month-6 minus baseline values). Results: Forty menopausal participants were equally, randomized into either the placebo or metformin group. The two groups had comparable metabolic parameters at baseline, except that the mean triglyceride level was higher in the metformin group than in the placebo group. The significant improvements found only in the metformin group were body mass index, fasting blood glucose, high-sensitivity C-reactive protein and 10-year risk of coronary heart disease (Framingham heart study) (P = 0.0004, P = 0.049, P = 0.035 and P = 0.029); whereas that only in the placebo group was high density lipoprotein cholesterol. However, there was no statistically significant difference in the improvement between the two groups. Conclusion: Metformin can improve some parameters of metabolic syndrome in middle-aged Thai women. Metformin is not superior to placebo for the improvement of cardiovascular risk factors.