Metformin vs myoinositol: which is better in obese polycystic ovary syndrome patients? A randomized controlled crossover study.

CONTEXT: Due to the central role of metabolic abnormalities in the pathophysiology of polycystic ovary syndrome (PCOS), insulin sensitizing agents have been proposed as a feasible treatment option.

OBJECTIVE: To investigate which is the more effective between metformin and myoinositol (MYO) on hormonal, clinical and metabolic parameters in obese patients with PCOS.

STUDY DESIGN: Crossover randomized controlled study.

PATIENTS: Thirty-four PCOS obese women (age: 25·62 ± 4·7 years; BMI: 32·55 ± 5·67 kg/m2 ) were randomized to receive metformin (850 mg twice a day) or MYO (1000 mg twice a day) for 6 months. After a 3 month washout, the same subjects received the other compound for the following 6 months.

MEASUREMENTS: Ultrasonographic pelvic examinations, hirsutism score, anthropometric and menstrual pattern evaluation, hormonal profile assays, oral glucose tolerance test (OGTT) and lipid profile at baseline and after 6 months of treatment were performed.

RESULTS: Both metformin and MYO significantly reduced the insulin response to OGTT and improved insulin sensitivity. Metformin significantly decreased body weight and improved menstrual pattern and Ferriman-Gallwey score. Metformin treatment was also associated with a significant decrease in LH and oestradiol levels, androgens and anti-müllerian hormone levels. None of these clinical and hormonal changes were observed during MYO administration.

CONCLUSIONS: Both treatments improved the glyco-insulinaemic features of obese PCOS patients, but only metformin seems to exert a beneficial effect on the endocrine and clinical features of the syndrome.