ReviewCureus2022
Effect of Metformin on Vitamin B12 Deficiency in Patients With Type 2 Diabetes Mellitus and Factors Associated With It: A Meta-Analysis.
Review in Cureus, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers.
What it found
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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.
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Who cites it
9 citing papers in PubMed, 15 citations in OpenAlex.
- Sebacic Acid: A Multifunctional Medium-Chain Dicarboxylic Acid in Metabolic Regulation and Tissue Regeneration.Current issues in molecular biology · 2026Review
- Exploring the risk of depression and suicide/self-injury in patients receiving GLP-1RAs combined with metformin versus GLP-1RA monotherapy: a real-word analysis of the FAERS database.Endocrine connections · 2026Article
- Comment on "Clinical medicine insights. Endocrinology and diabetes · 2026Article
- Metformin-induced vitamin B12 deficiency: An underdiagnosed cause of diabetic neuropathy.World journal of diabetes · 2025Review
- Long-Term Use of Metformin and Vitamin B12 Deficiency in Diabetes.Current drug safety · 2025Review
- Article
- Nutrition at the Intersection between Gut Microbiota Eubiosis and Effective Management of Type 2 Diabetes.Nutrients · 2024Review
- Vitamin B12 deficiency in diabetic patients treated with metformin: A cross-sectional study.PloS one · 2024Article
- Review
Corrections and comments
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Authors and funding
8 authors at 4 institutions in 5 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The current meta-analysis aims to explore the effect of metformin use on vitamin B12 deficiency in patients with type 2 diabetes mellitus (T2DM) and the factors associated with it. This meta-analysis followed the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines and the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. We searched PubMed and EMBASE from January 1, 2010, to October 31, 2022, to collect the studies that reported the effect of metformin on the deficiency of vitamin B12 in patients with T2DM and the factors associated with it. A total of 17 studies were included in the current meta-analysis. Among all the included studies, 13 were cross-sectional studies, 3 were retrospective cohorts, and one was a case-control study. The pooled rate of deficiency of vitamin B12 in patients receiving metformin (23.16%) was significantly higher compared to patients who were not on metformin (17.4%) (OR: 2.95, 95% CI: 2.18-4.00, p-value: 0.001). Factors significantly associated with vitamin B12 deficiency in patients with T2DM and receiving metformin include the duration of metformin use and a greater dose of metformin. In conclusion, our meta-analysis found that the prevalence of vitamin B12 deficiency is greater in patients receiving metformin compared to patients who did not receive metformin. Given the importance of vitamin B12 in nutrition, metformin-induced B12 decrease may be harmful to patients with T2DM. Supplemental vitamin B12 may be advantageous for those on metformin.
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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.