Effect of the insulin sensitizers metformin and pioglitazone on endothelial function in young women with polycystic ovary syndrome: a prospective randomized study

Abstract

Objective: To compare the effect of two different insulin sensitizers, metformin and pioglitazone, on endothelial function in women with polycystic ovary syndrome (PCOS).

Design: Prospective randomized study.

Setting: University Hospital endocrinology outpatient clinic.

Patient(s): Young women with PCOS (aged 23.3±4.9 years).

Intervention(s): Patients were assigned randomly to no treatment (n=14), metformin 850 mg two times per day (n=15), and pioglitazone 30 mg daily (n=14) for 6 months. Healthy age- and body mass index-matched women served as controls (n=14).

Main outcome measure(s): Brachial artery flow-mediated dilation was studied at baseline and 6 months.

Result(s): Women with PCOS had higher insulin resistance and hyperandrogenism indices and lower flow-mediated dilation compared with controls. The three groups of women with PCOS did not differ at baseline. No differences were observed at follow-up in women who received no treatment. Metformin and pioglitazone improved flow-mediated dilation to a similar extent, restoring it to normal values at 6 months. Both insulin sensitizers induced favorable changes in insulin resistance and hyperandrogenism indices in women with PCOS. Independent predictors of flow-mediated dilation improvement at 6 months were treatment with insulin sensitizers and reduction in insulin resistance.

Conclusion(s): In young women with PCOS, treatment with metformin or pioglitazone for 6 months induces a similar beneficial effect on endothelial function; this may be partially attributed to an improvement in insulin resistance. Further research is needed to investigate whether treatment with insulin sensitizers in women with PCOS also reduces cardiovascular risk.