Metformin versus oral contraceptive pill in polycystic ovary syndrome: a Cochrane review.

BACKGROUND

The object of this review was to compare metformin versus oral contraceptive pill (OCP) treatment in polycystic ovary syndrome.

METHODS

A systematic review and meta-analysis employing the principles of the Cochrane Menstrual Disorders and Subfertility Group was undertaken.

RESULTS

Four randomized controlled trials (RCTs) (104 subjects) were included. Limited data demonstrated no evidence of a difference in effect between metformin and the OCP on hirsutism, acne or development of type 2 diabetes mellitus. There were no trials assessing diagnosis of cardiovascular disease or endometrial cancer. Metformin, in comparison with the OCP, was less effective in improving menstrual pattern [Peto odds ratio (OR) 0.08, 95% confidence interval (CI) 0.01-0.45) and in reducing the serum total testosterone level weighted mean difference (WMD) 0.54, 95% CI 0.22-0.86] but more effective in reducing fasting insulin (WMD -3.46, 95% CI - 5.39 to -1.52) and not increasing fasting triglyceride (WMD -0.48, 95% CI - 0.86 to -0.09) levels. Limited data demonstrated no evidence of a difference in effect between the two therapies on reducing fasting glucose or total cholesterol levels and severe adverse events.

CONCLUSIONS

The limited RCT evidence to date does not show adverse metabolic risk with the use of the OCP compared with metformin. Further long-term RCTs are required.