Insulin-sensitizing agents as primary therapy for patients with polycystic ovarian syndrome.

Background: This paper is a systematic review of metformin versus clomiphene citrate (CC) in women with polycystic ovary syndrome (PCOS).
Methods: Meta-analysis Of Observational Studies in Epidemiology (MOOSE) and QUality Of Reporting Of Meta-analyses (QUOROM) guidelines were followed. A systematic computerized literature search was done of seven bibliographic databases. Inclusion criteria included cohort and randomized controlled trials (RCT) of women with PCOS and the following medications: metformin versus placebo; metformin versus CC; metformin plus CC versus placebo plus CC. Rev-man 4.1 and Metaview 4.0 were used to analyse data. Relative risk (RR) estimates were presented. A chi2-test determined the significance of the association. Heterogeneity was determined by the Cochran Q-test.
Results: Metformin was 50% better than placebo for ovulation induction in infertile PCOS patients [RR 1.50; 95% confidence interval (CI) 1.13, 1.99]. Metformin was also of benefit in non-infertile (i.e. patients with PCOS who were not complaining of infertility) PCOS patients for cycle regulation compared to placebo (RR 1.45; CI 1.11, 1.90). Metformin was not of confirmed benefit versus placebo for achievement of pregnancy (RR 1.07; CI 0.20, 5.74). Metformin plus CC may be 3-4-fold superior to CC alone for ovulation induction (RR 3.04; CI 1.77, 5.24) and pregnancy (RR 3.65; CI 1.11, 11.99) in women with PCOS.
Conclusions: Metformin is effective for ovulation induction and cycle regulation in this group of patients. Metformin plus CC appears to be very effective for achievement of pregnancy compared to CC alone. No RCTs directly compare metformin to CC but the need for such a trial exists.