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Thyroidal effect of metformin treatment in patients with polycystic ovary syndrome

Mario Rotondi, Carlo Cappelli, Flavia Magri, Roberta Botta, Rosa Dionisio, Carmelo Iacobello, Pasquale De Cata, Rossella Elena Nappi et al.

Clinical Endocrinology, 2011

24 participants · 69 citations

Abstract

OBJECTIVE: Metformin is widely used for the treatment of type 2 diabetes. Growing evidence supports the beneficial effects of metformin also in patients with polycystic ovary syndrome (PCOS). It was recently reported that metformin has a TSH-lowering effect in hypothyroid patients with diabetes being treated with metformin. DESIGN: Aim of this study was to evaluate the effect of metformin treatment on the thyroid hormone profile in patients with PCOS. PATIENTS AND MEASUREMENTS: Thirty-three patients with PCOS were specifically selected for being either treated with levothyroxine for a previous diagnosis of hypothyroidism (n = 7), untreated subclinically hypothyroid (n = 2) or euthyroid without levothyroxine treatment (n = 24) before the starting of metformin. The serum levels of TSH and FT(4) were measured before and after a 4-month period of metformin therapy. RESULTS: Thyroid function parameters did not change after starting metformin therapy in euthyroid patients with PCOS. In the 9 hypothyroid patients with PCOS, the basal median serum levels of TSH (3·2 mIU/l, range = 0·4-7·1 mIU/l) significantly (P < 0·05) decreased after a 4-month course of metformin treatment (1·7 mIU/l, range = 0·5-5·2 mIU/l). No significant change in the serum levels of FT4 was observed in these patients. The TSH-lowering effect of metformin was not related to the administered dose of the drug, which was similar in euthyroid as compared with hypothyroid patients with PCOS (1406 ± 589 vs 1322 ± 402…

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Evidence Hub reads this as a clinical trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 24 participants or records.

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