Evaluating the equivalence of clomiphene citrate with and without metformin in ovulation induction in PCOS patients

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To evaluate the benefit of Metformin added to Clomiphene Citrate in a primary ovulation induction protocol in PCOS patients. Prospective randomised controlled study. Tygerberg Academic Hospital, Stellenbosch University and the Institute of Reproductive Medicine at Vincent Pallotti Hospital, Cape Town. 107 patients presenting with PCOS. Group A was pre-treated with metformin 850 mg twice a day for at least 6 weeks before clomiphene was added and the metformin was used throughout the study period. Group B received clomiphene without pre-treatment with metformin. In both groups clomiphene was given at a starting dose of 50 mg day 4-8 and increase with increments of 50 mg to a maximum of 150 mg if no response was achieved. The ovulation rate achieved in women in the M+C/C arm was 34/52 (65.4%) compared to 36/55 (65.5%) in the C/C arm. The treatment effect ((M+C/C) - C/C) is 0% with 95% confidence interval of -18.1% to 18%. The per protocol ovulation results were 34/42 (81%) in the M+C/C arm compared to 36/48 (75%) in the C/C arm. The ovulation rate difference was 6% with 95% confidence interval -11% to 22%. In a comparison of successful ovulating versus non-ovulating women from the trial the following were significant baseline determinants: lower median weight in the ovulating group (77 kg versus 86 kg, p = .021), lower median bmi (29.0 versus 32.9, p = .009), lower median DHEAS at baseline (4.6 compared to 7.0, p = .049), lower median 17OH-progesterone (2.2 versus 4.6, p = .027) and higher baseline median SHBG ( 37.8 compared to 28.5, p = .036). Although identical ovulation rates were observed in both arms equivalence could not be concluded with respect to the specified criteria.