Is there a dose–response relationship of metformin treatment in patients with polycystic ovary syndrome?

Human Reproduction, 07/23/2012

Metformin exerted an overall positive effect on the clinical and endocrine–metabolic features of PCOS. The degree of these effects was independent of the administered dosage in every range of basal body mass index (BMI).

Methods

  • A multicentric cohort prospective study
  • A total of 250 PCOS women were enrolled, 49 lost to follow–up
  • Menstrual cyclicity, hormonal assays, oral glucose tolerance test, lipid profile and ultrasonographic pelvic examination were evaluated at the baseline and after 6 months of metformin treatment at different doses (1000, 1500 and 1700 mg).
  • A total of 201 PCOS patients completed the study without protocol violations in three university hospitals: seventy–three patients from Centre A (treated with metformin 500 mg twice a day), 60 patients from Centre B (treated with metformin 500 mg three times a day) and 68 patients from Centre C (treated with metformin 850 mg twice a day).

Results

  • Metformin exerted an overall positive effect on the clinical and endocrine–metabolic features of PCOS.
  • The degree of these effects was independent of the administered dosage in every range of basal body mass index (BMI).
  • Patients were stratified according to their insulinaemic status, scattered inter–doses differences were found in some of the outcome measures.
  • Patients who exhibited an increase of >2 menstrual cycles/year were considered as responders to treatment.
  • This is the first study which systematically analyses the effect of different doses of metformin on clinical, hormonal and metabolic features of PCOS. On the basis of results, higher doses are no more effective than lower doses.

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