Endocrine and metabolic effects of metformin versus ethinyl estradiol-cyproterone acetate in obese women with polycystic ovary syndrome: A randomizedstudy

Metformin, a biguanide antihyperglycemic drug, has been shown to improve ov arian function and glucose metabolism in women with polycystic ovary syndro me (PCOS), but results concerning its effects on insulin sensitivity are co ntroversial. Oral contraceptive pills are commonly used in the treatment of PCOS; but, like metformin, their influence on insulin sensitivity is not w ell known. We randomized 32 obese (body mass index > 27 kg/m(2)) women with PCOS, either to metformin (500 mg x 2 daily for 3 months, then 1000 mg x 2 daily for 3 months) or to ethinyl estradiol (35 mu g)-cyproterone acetate (2 mg) oral contraceptive pills (Diane Nova) for 6 months. Metformin signif icantly decreased the waist-to-hip ratio, serum testosterone, fasting free fatty acid, and insulin concentrations and improved oxidative glucose utili zation and menstrual cyclicity, with slight (but nonsignificant) improvemen ts in insulin hepatic extraction and insulin sensitivity. Diane Nova signif icantly decreased serum testosterone and increased serum sex hormone-bindin g globulin concentrations and glucose area under the curve during oral gluc ose tolerance test. It is concluded that metformin, probably by way of its effect on adipose tissue, leads to reduction of hyperinsulinemia and concom itant improvement in the menstrual pattern; and therefore, it offers a usef ul alternative treatment far obese, anovulatory women with PCOS. Despite sl ight worsening of glucose tolerance, Diane Nova is an efficient treatment f or women with hyperandrogenism and hirsutism.