An RCT of metformin versus orlistat for the management of obese anovulatory women

Abstract

BACKGROUND: Treatment of obesity-related anovulation poses a significant clinical challenge. Occasionally, the use of antiobesity medications such as orlistat or insulin sensitizing agents such as metformin is sometimes indicated in these patients. This study aimed to compare the effects of metformin and orlistat for improving ovulation in obese anovulatory women. METHODS: This was an open-label RCT. A total of 40 women were randomized to receive either metformin (n = 20) or orlistat (n = 20). BMI as well as the androgen profile and the ovulatory status were assessed at baseline and at four weekly intervals for 3 months. Different anthropometric and endocrine parameters were also assessed as possible predictors of ovulation. RESULTS: There was no significant difference between the two study arms regarding the ovulation rate for metformin and orlistat [40 (n = 8/20) and 25 (n = 5/20), respectively, P = 0.31]. Both arms showed a significant drop in the BMI, testosterone and androstendione concentrations (P < 0.05), but there was no difference between the two arms. Patients who ovulated had significantly lower concentrations of baseline LH, androstendione, dehydroepiandrosterone and free androgen index (P < 0.05). Among these factors, a low baseline LH was found to be the only independent predictor of ovulation (area under curve, 0.85). CONCLUSIONS: Both metformin and orlistat show a similar effect on weight loss, ovulation rates and androgen concentrations. However, the effects on ovulation rates need to be confirmed in larger studies. The presence of a low baseline serum LH was found to be the most important predictor of ovulation.