Associations between metformin use and vitamin B12 levels, anemia, and neuropathy in patients with diabetes: a meta-analysis
Abstract
BACKGROUND: Metformin is first-line therapy for patients with diabetes. However, it may lower vitamin B12 concentrations, which could have hematological or neurological implications. This meta-analyses reviewed all available studies on associations between metformin use and vitamin B12 levels, anemia, and neuropathy in diabetic patients.
METHODS: PubMed, Web of Knowledge, Cochrane Library, and Embase were searched to identify all relevant studies published in English prior to March 2018. Pooled risk ratios (RRs) and 95% confidence intervals (CIs) were calculated for dichotomous outcomes and pooled mean differences (MDs) and 95% CIs were calculated for continuous outcomes.
RESULTS: Thirty-one studies were included in the meta-analyses. Compared with diabetic patients not taking metformin, patients taking metformin had a significantly higher risk of vitamin B12 deficiency (RR 2.09; 95% CI 1.49, 2.93; P < 0.0001; I2 = 64%) and significantly lower serum vitamin B12 concentrations (MD -63.70; 95% CI -74.35, -53.05] pM; P < 0.00001; I2 = 87%), which depended on dose and duration of treatment. Metformin use was also associated with significantly greater percentage decrease in serum vitamin B12 concentrations from baseline in diabetic patients (MD -14.68%; 95% CI -17.98%, -11.39%; P < 0.00001; I2 = 33%). Analyses revealed no significant association between metformin use and the prevalence of anemia or neuropathy.
CONCLUSIONS: Metformin use led to significantly lowered vitamin B12…
How strong is the evidence?
Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid.
Read the paper
Related studies
- Metformin as an adjuvant in breast cancer treatment
- Metformin Lysosomal Targeting: A Novel Aspect to Be Investigated for Metformin Repurposing in Neurodegenerative Diseases?
- Aberrant HSF1 signaling activation underlies metformin amelioration of myocardial infarction in mice
- Metformin induces ZFP36 by mTORC1 inhibition in cervical cancer-derived cell lines
- Protein Interaction Network for Identifying Vascular Response of Metformin (Oral Antidiabetic)
- Preventing Long COVID With Metformin
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.