Long-term efficacy of metformin in overweight-obese PCOS: longitudinal follow-up of retrospective cohort

Abstract

Objective: Long-term efficacy of metformin in polycystic ovarian syndrome ( PCOS) apart from in those with impaired glucose tolerance or diabetes remains unproven. We aimed to evaluate the impact of metformin in overweight-obese patient s with PCOS and normal baseline glycemic homeostasis. Methods: A 10-year longitudinal follow-up of a retrospective cohort comprising 159 patients with PCOS defined by Rotterdam criteria, BMI ≥25 kg/m2 and normal initial glucose homeostasis (age 28.4 ± 6.4 years, BMI 34.9 ± 6.6 kg/m 2) that had been receiving metformin 1000 mg BID. Collection data contained 6085 time-points including anthropometric, hormonal and metabolic parameters. Results: After the first year body mass (BM) decreased for 3.9 ± 6.8 kg (P < 0.001) and remained stable during the following 3 years. Menstrual frequen cy (MF) increased to 3.0 ± 3.9 bleeds/year (P < 0.001) after first year to over 11 bleeds/year in the followi ng years. The total testosterone and androstenedione decreased to 15.4 ± 47.9% and 11.3 ± 46.4% within first year, with further decrease in tot al testosterone and androstenedione to 37.8 ± 61.8 and 24.8 ± 40.5% at the fifth yea r of the follow-up. The total conversion rate to prediabetes and diabetes was extremely low throughout observation period. Less than 25% of patients continued with me tformin for more than 5 years with further dropout to only 6% on metformin therapy at the tenth year of follow-up. Conclusions: Long-term metformin treatment of overweight-obese women with P COS and normal baseline glycemic homeostasis resulted in reduction and stabilization of BM, improvements of MF and androgen profile and low conversion rate to diabetes.

Keywords

• metformin
• pcos
• obesity
• diabetes
• impaired glucose tolerance