Metformin treatment for small benign thyroid nodules in patients with insulin resistance.

摘要

OBJECTIVE: It has been shown that patients with insulin resistance (IR) have a higher prevalence of thyroid nodules and bigger thyroid glands. We evaluated the ability of metformin (M) alone or combined with levothyroxine (L-T) to reduce the nodular size in benign thyroid hyperplastic nodules (<2 cm in diameter). METHODS: A total of 66 women with IR and nodular hyperplasia, diagnosed by fine needle aspiration biopsy (FNAB), who completed this prospective 6-month duration protocol, were assigned to one of four groups: Group I (GI) (n = 14), patients treated with M; GII (n = 18), patients treated with M plus L-T; GIII (n = 19), patients treated with L-T; and GIV (n = 15), patients without any treatment. RESULTS: All groups of included patients had no statistically significant different mean baseline characteristics. Patients from GII and GIII showed drops in thyroid-stimulating hormone (TSH) levels and GI and GII normalized the homeostasis model assessment (HOMA) index after treatment, as expected. The median baseline size of all included nodules was 298 mm(3) approximately 0.84 cm in diameter (range, 32-3,616 mm(3)). After treatment, patients of Group I and II showed significant reductions in their nodule size [median reduction, 108.50 mm(3) (30%) and 184.5 mm(3) (55%), P < 0.008 and P < 0.0001, respectively]. Patients in GIII and GIV did not have a significant reduction of their nodules [P = not significant (N.S.)]. CONCLUSIONS: We conclude that M produced a significant decrease in the nodular size in patients with IR and small thyroid nodules, whereas the combination of M with L-T was the best treatment in these women.