Metformin ameliorates insulin resistance, thyroid nodules and thyroid function

Shuhong Ji; Ruixin Gao; Qinghua Gao; Lihong Leng; Ningning Gai

Metformin ameliorates insulin resistance, thyroid nodules and thyroid function

Am J Transl Res. 2023 Oct 15;15(10):6180-6188. eCollection 2023.

Authors

Shuhong Ji¹, Ruixin Gao², Qinghua Gao³, Lihong Leng⁴, Ningning Gai⁵

Affiliations

¹ Department of Endocrinology, Dezhou Hospital of Traditional Chinese Medicine Dezhou, Shandong, China.
² Department of Endocrinology, Dongying Hospital of Traditional Chinese Medicine Dongying, Shandong, China.
³ Department of Endocrinology, Central Hospital of Lijin Dongying, Shandong, China.
⁴ Department of Anesthesiology, Yantai Penglai Traditional Chinese Medicine Hospital Yantai, Shandong, China.
⁵ Department of Endocrinology, Yantai Laiyang Central Hospital Laiyang, Shandong, China.

PMID: 37969194
PMCID: PMC10641348

Abstract

Objective: To evaluate the ameliorative impact of metformin on insulin resistance (IR), as well as thyroid nodules (TNs) and function in TN patients with IR.

Methods: The clinical data of 128 TN patients with IR admitted to Yantai Laiyang Central Hospital from July 2018 to March 2020 were retrospectively analyzed and categorized into a control group (CNG, n = 64) and a study group (SG, n = 64). Patients in the CNG received standard lifestyle intervention, while those in the SG received standard lifestyle intervention in conjunction with metformin therapy for 1 year of course. Weight-related indicators, IR, thyroid function, TN diameter, and oxidative stress levels were compared between the two groups before and after treatment. Additionally, the safety of metformin was evaluated.

Results: Before treatment, no significant differences were observed between the two groups in fasting plasma glucose (FPG), 2-h postprandial glucose (2hPG), glycated hemoglobin (HbA1c), fasting insulin (FINS), homeostatic model assessment of insulin resistance (HOMA-IR), systolic blood pressure (SBP), diastolic blood pressure (DBP), thyroid-stimulating hormone (TSH), malondialdehyde (MDA), TN diameter, and thyroid volume (P > 0.05). After treatment, significant statistical differences were observed in the aforementioned indicators between the two groups (P < 0.05). After 1 year of treatment, the SG exhibited lower levels of FPG, 2hPG, HbA1c, FINS, HOMA-IR, SBP, DBP, TSH, MDA, TN diameter, and thyroid volume, and showed higher levels of HOMA-β, superoxide dismutase, and glutathione peroxidase levels compared to before treatment (P < 0.05). The incidence of adverse reactions in the SG was significantly higher than that in the CNG (P < 0.05). Taking metformin and free thyroxine (FT4) were protective factors for TSH (P < 0.05).

Conclusion: Metformin could significantly improve IR and oxidative stress levels, regulate TSH levels, and shrink TNs in TN patients with IR, with high safety. The administration of metformin and FT4 were identified as protective factors for positive prognosis.

Keywords: Metformin; insulin resistance; oxidative stress; thyroid nodules.