| Objective:To evaluate the effects of metformin on serum vitamin B12, folic acid and homocysteine levels in patients with type 2 diabetes mellitus.Methods:The Cochrane Library, EMBASE, PubMed, CBM, CNKI, VIP and Wanfang database were searched to collect randomized controlled trials (RCTs) exploring the association between metformin and serum vitamin B12 levels in type 2 diabetic patients. Two researchers independently screened literature, assessed the risk of bias of included studies and extracted data. RevMan5.3 software was used for this Meta-analysis.Results:A total of 5 RCTs were included.The results of Meta-analysis showed: Serum vitamin B12 levels in metformin group were significantly lower than in placebo group (MD=-55.86,95%CI(-86.89,-24.84), P=0.0004). Subgroup analysis showed that serum vitamin B12 concentrations were negatively correlated with the duration of diabetes, course and dose of metformin treatment. The serum homocysteine (Hcy) levels in metformin group were higer than in placebo group (MD=2.44. (1.41,3.46), P< 0.00001); There were no statistical differences in serum folic acid levels between the two groups [MD=-2.39,95% CI (-4.93,0.15), P= 0.06].;The incidence of adverse reactions in the metformin group was higher than that in the placebo group [RR=2.0,95%CI (1.32,3.03), P= 0.001].Conclusion:Metformin may lead to lower serum vitamin B12 and elevated Hcy levels in type 2 diabetic patients, but has no significant effect on folic acid level. More high quality studies are needed to confirm this. |
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