Endocrine Abstracts

Background: Use of metformin in women with polycystic ovary syndrome (PCOS) is becoming increasingly accepted and widespread but clinical practice is ahead of the evidence.
Methods: We extracted results from the seven published studies of metformin use in PCOS that include control elements quantifiably similar to the experimental arm. We also restricted our analysis to the studies with a systematic longitudinal examination of ovulatory function and metabolic parameters.
Results: from an amalgamation of data from these studies we calculate that on average, women treated with metformin have one more ovulatory event and menstrual period in every five months, i.e. increasing from one ovulation per five months to two. The accumulated data also suggests that metformin reduces body mass index by an average of 4.4% in women with PCOS Vs average placebo reductions of 0.5% (p<0.05). Androgen measures were reduced by 21% with metformin treatment compared to placebo reductions of 2% (p<0.05). However, average changes in fasting insulin (-27% in metformin Vs -16% in placebo group) and SHBG (+5% Vs +4%) were more variable and not significant.
Conclusion: Thus, current best data in this area suggest metformin has on average a modest effect on ovulation, and that ovulation frequency is by no means restored to normal in every woman with metformin use. In addition, metformin treatment leads to significant reductions in BMI and androgenicity. Data on effects on hirsutism and acne are limited at present, such that no recommendations can be made. Presentation of these findings should lead to a more judicious use of metformin in women with PCOS and a more structured approach to future research.
Harborne L, Fleming R, Lyall H, Norman JE and Sattar N. A review of the evidence for the use of metformin in polycystic ovary syndrome. Lancet (In press).