Association of oral contraceptive and metformin did not improve insulin resistance in women with polycystic ovary syndrome

Objective: to compare clinical and laboratory parameters in women with polycystic ovary syndrome (PCOS) using metformin or combined oral contraceptive (COC) after 6 months. Methods: retrospective study analyzing records of patients with PCOS using the Androgen Excess and Polycystic Ovary Syndrome (AE-PCOS) Society criteria. The groups were: I-COC (21 tablets, pause of 7 days; n=16); II-metformin (850mg 12/12h, n=16); III-COC plus metformin (n=9). Body mass index (BMI), acne (% of improvement), modified Ferriman-Gallway index and menstrual cycle index (MCI), luteinizing hormone (LH), follicle-stimulating hormone (FSH), total testosterone (TT), androstenedione (A) and homeostasis model assessment: insulin resistance (HOMA-IR) index were assessed. Results: isolated use of COC compared to metformin was better regarding to acne, Ferriman index, MCI, LH, TT and A levels. On the other hand, metformin was better in the HOMA-IR index (4.44 and 1.67 respectively, p=0.0007). The association COC plus metformin, compared to metformin alone shows the maintenance of improvement of acne, Ferriman index, MCI, and testosterone levels. The HOMA-IR index remained lower in the metformin alone group (4.19 and 1.67, respectively; p=0,046). The comparison between COC plus metformin and COC alone, in turn, shows no difference in the improvement of acne, Ferriman index, MCI, LH, TT and A levels, indicating that the inclusion of metformin did not lead to additional benefits in these parameters. Still, the HOMA-IR index was similar in both groups (4.19 and 4.44 respectively; p=0.75), showing that the use of metformin associated with COC may not improve insulin resistance as much as it does if used alone. Conclusion: our data suggest that the combination of metformin and contraceptive does not improve insulin resistance as observed with metformin alone.