Metformin treatment of women with PCOS has been shown to improve ovarian function, reduce hyperandrogenicity and induce weight loss. The aim of this prospective study was to investigate the nature of the weight loss in obese women with PCOS, using 2 dose regimes.
Methods: Obese (body mass index [BMI] > 29 kilograms /m2) women with PCOS (n = 44) were recruited to the study, and randomised to receive either 1500mg metformin daily (n = 22), or 2550mg metformin daily (n = 22). Inclusion criteria were obesity (BMI>29), associated with 2 of: oligomenorrhoea, raised free androgen index (FAI, >7), or ultrasound evidence of polycystic ovaries. They were assessed for anthropometric data, ovarian volume, circulating reproductive hormones, glycaemic and lipid parameters prior to starting treatment, and after 8 months.
Results: Significant reductions in weight were recorded on both doses of metformin at 8 months. The 1500mg group lost 3.3 Kg, representing a reduction in mean BMI from 38.4 to 37.3, while the 2550mg group lost 5.0 Kg representing a decline from 36.2 to 34.3. The weight loss was associated with equal reductions in circumference of the waist and the hip, such that the waist/hip ratios remained unchanged, at 0.86 in both groups, before and after treatment. Ovarian volumes remained unchanged by treatment. The circulating total testosterone did not decline in either treatment group, and there was no change in the circulating sex hormone binding globulin. The FAI values remained unchanged in both groups (1500mg -10.5 to 12.9; 2550mg - 10.8 to 9.8).
Discussion: These results showed that moderate weight loss was induced with metformin treatment in obese women with PCOS, using both dose schedules. The higher dose was more effective. Expected associated changes in anthropometric and endocrine assessments did not take place.