Trial reportDiabetes care2009
TSH-lowering effect of metformin in type 2 diabetic patients: differences between euthyroid, untreated hypothyroid, and euthyroid on L-T4 therapy patients.
Trial report in Diabetes care, 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 68 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
68 citing papers in PubMed, 2 syntheses or guidelines pooled it, 167 citations in OpenAlex.
- The effect of metformin therapy on serum thyrotropin and free thyroxine concentrations in patients with type 2 diabetes: a meta-analysis.Scientific reports · 2023Pooled it
- Subclinical Hypothyroidism and Type 2 Diabetes: A Systematic Review and Meta-Analysis.PloS one · 2015Pooled it
- Effect of metformin on thyroid function tests in patients with subclinical hypothyroidism: an open-label randomised controlled trial.Journal of endocrinological investigation · 2019Trial
- Metformin effect on TSH in subclinical hypothyroidism: randomized, double-blind, placebo-controlled clinical trial.Endocrine · 2018Trial
- Effects of SGLT-2 inhibitors on thyroid-stimulating hormone and systemic immune-inflammation index in type 2 diabetes: a retrospective study.BMC endocrine disorders · 2026Observational
- Another pleiotropic effect of SGLT2 inhibitors: Is it a new frontier in thyroid function regulation?Thyroid research · 2026Review
- Metformin and Myo-Inositol: A Comparative Analysis.Gynecologic and obstetric investigation · 2026Review
- The Impact of Metformin on Plasma Prolactin Levels in Antipsychotics-Treated Men With Hyperprolactinemia and Early-Onset Androgenic Alopecia.Clinical endocrinology · 2025Article
- Semaglutide therapy and iatrogenic thyrotoxicosis.Endocrinology, diabetes & metabolism case reports · 2025Article
- The Effect of Metformin on Pituitary Function in Postmenopausal Women with Subclinical Hypothyroidism and Macroprolactinemia: A Single-Center Prospective Case-Control Study.Pharmaceuticals (Basel, Switzerland) · 2025Article
- The Association between Vitamin D Status and the Impact of Metformin on Hypothalamic-Pituitary-Thyroid Axis Activity in Women with Subclinical Hypothyroidism.Pharmaceutics · 2024Article
- Autoimmune Thyroiditis Mitigates the Effect of Metformin on Plasma Prolactin Concentration in Men with Drug-Induced Hyperprolactinemia.Pharmaceuticals (Basel, Switzerland) · 2024Article
- Interleukin-6 and thyroid-stimulating hormone index predict plaque stability in carotid artery stenosis: analyses by lasso-logistic regression.Frontiers in cardiovascular medicine · 2024Article
- Effects of Metformin Therapy on Thyroid Volume and Functions in Patients with Newly Diagnosed Type 2 Diabetes Mellitus: A Single-center Prospective Study.Endocrine, metabolic & immune disorders drug targets · 2024Observational
- Effects of thyroid hormones modify the association between pre-pregnancy obesity and GDM: evidence from a mediation analysis.Frontiers in endocrinology · 2024Article
- Epidemiological, Pathophysiological, and Clinical Considerations on the Interplay between Thyroid Disorders and Type 2 Diabetes Mellitus.Medicina (Kaunas, Lithuania) · 2023Review
- Sensitivity to thyroid hormone indices are associated with papillary thyroid carcinoma in Chinese patients with thyroid nodules.BMC endocrine disorders · 2023Article
- Vitamin D Status Determines the Impact of Metformin on Gonadotropin Levels in Postmenopausal Women.Journal of clinical medicine · 2023Article
- Association between sensitivity to thyroid hormones and dyslipidemia in patients with coronary heart disease.Endocrine · 2023Article
- Association Between Thyroid Parameters and Subclinical Atherosclerosis in Hospitalised Euthyroid Patients with Type 2 Diabetes Mellitus.Diabetes, metabolic syndrome and obesity : targets and therapy · 2023Article
8 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
11 authors at 4 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveTo assess the interplay between metformin treatment and thyroid function in type 2 diabetic patients. RESEARCH DESIGN AND
methodsThe acute and long-term effects of metformin on thyroid axis hormones were assessed in diabetic patients with primary hypothyroidism who were either untreated or treated with levothyroxine (L-T4), as well as in diabetic patients with normal thyroid function.
resultsNo acute changes were found in 11 patients with treated hypothyroidism. After 1 year of metformin administration, a significant thyrotropin (TSH) decrease (P < 0.001) was observed in diabetic subjects with hypothyroidism who were either treated (n = 29; from 2.37 +/- 1.17 to 1.41 +/- 1.21 mIU/l) or untreated (n = 18; 4.5 +/- 0.37 vs. 2.93 +/- 1.48) with L-T4, but not in 54 euthyroid subjects. No significant change in free T4 (FT4) was observed in any group.
conclusionsMetformin administration influences TSH without change of FT4 in patients with type 2 diabetes and concomitant hypothyroidism. The need for reevaluation of thyroid function in these patients within 6-12 months after starting metformin is indicated.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.