Abstract
AbstractType 2 diabetes and thyroid function disorders are two common chronic endocrine disorders with the high prevalence in various populations. Metformin is well established as the first-line drug therapy for managing diabetes mellitus. In this meta-analysis, we aimed to determine the effect of metformin on serum TSH and FT4 concentrations in patients with type 2 diabetes. We searched PubMed, Scopus, web of science, Cochrane library, and google scholar to collect information on the effect of metformin on serum TSH and FT4 levels. Demographic and clinical information and serum TSH and FT4 concentrations before and after metformin treatment were extracted. Studies on patients over 18 years of age were included. A total of 11 studies including 1147 patients were selected for the final analysis. In hypothyroid patients, the TSH level decreased significantly after treatment with metformin (Hedges’s g:1.55, 95%CI 0.93–2.16, p-value < 0.001); FT4 level increased slightly after taking metformin, but the increase was not significant (Heddges’s g: − 0.30, 95%CI − 0.90,0.31, p-value = 0.34). In euthyroid subjects, the slight decrease found in TSH and FT4 concentrations was not statistically significant. Metformin reduces TSH levels in hypothyroid patients; however, it has no effect on TSH levels in euthyroid patients. Metformin does not affect serum FT4 levels in euthyroid and hypothyroid patients.
Publisher
Springer Science and Business Media LLC
Reference26 articles.
1. Hollowell, J. G. et al. Serum TSH, T4, and thyroid antibodies in the United States population (1988 to 1994): National health and nutrition examination survey (NHANES III). J. Clin. Endocrinol. Metab. 87, 489–499 (2002).
2. Delshad, H., Mehran, L., Tohidi, M., Assadi, M. & Azizi, F. The incidence of thyroid function abnormalities and natural course of subclinical thyroid disorders, Tehran, IR Iran. J. Endocrinol. Invest. 35, 516–521 (2012).
3. Derakhshan, A. et al. Sex specific incidence rates of type 2 diabetes and its risk factors over 9 years of follow-up: Tehran lipid and glucose study. PLoS ONE 9, e102563 (2014).
4. Talwalkar, P., Deshmukh, V. & Bhole, M. Prevalence of hypothyroidism in patients with type 2 diabetes mellitus and hypertension in India: a cross-sectional observational study. Diabetes, Metab. Syndr. Obes.: Targets Ther. 12, 369 (2019).
5. Apostolova, N. et al. Mechanisms of action of metformin in type 2 diabetes: Effects on mitochondria and leukocyte-endothelium interactions. Redox Biol. 34, 101517 (2020).