Endocrine Abstracts

Introduction: Metformin is now one of the most common treatments for PCOS. However controversy exists about the usefulness of metformin in PCOS women with normal insulin sensitivity and normal weight. The aim of this study was to compare efficacy of metformin treatment for the purpose of restoration of ovulation in lean and obese women with polycystic ovary syndrome.

Design: Thirty-six unovulatory women with PCOS (21 lean with mean body mass index (BMI) 21.4±2.3 kg/m² and 15 obese with BMI 32.3±3.3 kg/m²) received metformin 1700 mg/day during 6 months. We estimated ovulation induction (by ultrasound scanning), change in menstrual cycle, anthropometric measurements, endocrine parameters and insulin sensitivity.

Results: A total of 20 lean and 14 obese women completed the trial. The groups were comparable by age, androgen levels and severity of menstrual dysfunction at baseline. Ten obese patients (67%) and one lean patient (5%) had resistance to insulin (homeostasis model assessment (HOMA) index >2.5), P<0.001. Lean women with PCOS treated with metformin had restoration of menstrual function (55%) and ovulation (45%) more often than obese women with PCOS (only one patient – 7% – responded to the treatment), P=0.018. Significant decrease of testosterone level (from 3.1±1.0 to 2.7±0.8 nmol/l; P=0.049), fasting glucose (from 5.2±0.4 to 4.9±0.4 mmol/l, P=0.013) and HOMA (from 1.6±0.7 to 1.2±0.7, P=0.045) during metformin treatment was shown only in lean women with PCOS. There was no change in BMI and waist circumference in both groups.

Conclusions: Treatment with metformin 1700 mg daily was more effective in lean than in obese women with PCOS. Its efficacy was independent of initial surrogate markers of resistance to insulin.