A comparison between rimonabant and metformin in reducing biochemical hyperandrogenaemia and insulin resistance in patients with polycystic ovary syndrome (PCOS): a randomized open-label parallel study

Weight loss and metformin therapy are reported to be beneficial in improving the biochemical hyperandrogenaemia and insulin resistance of polycystic ovary syndrome (PCOS). Rimonabant has been found to reduce weight and improve the metabolic profile in patients with obesity, type 2 diabetes and metabolic syndrome. To compare the effects of insulin sensitization with metformin to weight reduction by rimonabant on biochemical hyperandrogenaemia and insulin resistance in patients with PCOS. A randomized, open-label parallel study. Endocrinology outpatient clinic in a referral centre. Twenty patients with PCOS and biochemical hyperandrogenaemia with a body mass index (BMI) >= 30 kg/m(2) were recruited. Patients were randomized to 1.5 g daily of metformin or 20 mg daily of rimonabant. The primary end-point of the study was a change in total testosterone. After 12 weeks of rimonabant there was a significant reduction (mean +/- SEM) in weight (104.6 +/- 4.6 vs. 98.4 +/- 4.7 kg, P < 0.01), waist circumference (116.0 +/- 3.3 vs. 109.2 +/- 3.7 cm, P < 0.01), hip circumference (128.5 +/- 4.0 vs. 124.1 +/- 4.2 cm, P < 0.03), waist-hip ratio (0.90 +/- 0.02 vs. 0.88 +/- 0.01, P < 0.01) free androgen index (FAI) (26.6 +/- 6.1 vs. 16.6 +/- 4.1, P < 0.01), testosterone [4.6 +/- 0.4 vs. 3.1 +/- 0.3 nmol/l (132.7 +/- 11.5 vs. 89.4 +/- 8.65 ng/dl), P < 0.01] and insulin resistance as measured by the homeostasis model assessment (HOMA) method (4.4 +/- 0.5 vs. 3.4 +/- 0.4, P = 0.05). There was no change in any of these parameters in the metformin-treated group. This study suggests that the weight loss through rimonabant therapy may be of use in patients with PCOS and appears superior to insulin sensitization by metformin in reducing the FAI and insulin resistance in obese PCOS patients treated over a 12-week period.