目的 探討二甲雙胍對(duì)2型糖尿病患者維生素B12（Vit B₁₂）、甲基丙二酸（MMA）水平和神經(jīng)病變的影響。方法 納入2型糖尿病患者60例，按治療方法分為觀察組30例，對(duì)照組30例。兩組均按入組前的劑量繼續(xù)使用胰島素治療，此外，觀察組給予二甲雙胍治療，對(duì)照組給予安慰劑治療。兩組療程均為3年，通過(guò)定期門(mén)診對(duì)患者進(jìn)行隨訪(fǎng)，比較兩組治療前后空腹血糖（FPG）、餐后2 h血糖（PPPG）、糖化血紅蛋白（HbA1c）、Vit B₁₂、MMA和神經(jīng)病變?cè)u(píng)分的變化。結(jié)果 兩組治療后FPG、PPPG、HbA1c均顯著下降，同組治療前后比較差異有統(tǒng)計(jì)學(xué)意義（P<0.05），且觀察組顯著低于對(duì)照組，組間差異有統(tǒng)計(jì)學(xué)意義（P<0.05）。兩組治療后腎小球?yàn)V過(guò)率（eGFR）均下降，同組治療前后比較差異有統(tǒng)計(jì)學(xué)意義（P<0.05）；但組間無(wú)顯著差異。治療后，兩組MMA均顯著上升，同組治療前后比較差異有統(tǒng)計(jì)學(xué)意義（P<0.05）；且觀察組更明顯，組間差異有統(tǒng)計(jì)學(xué)意義（P<0.05）；VitB₁₂均顯著下降，且觀察組更明顯（P<0.05）；兩組神經(jīng)病變?cè)u(píng)分有所上升，但組間無(wú)顯著差異。結(jié)論 二甲雙胍不僅會(huì)降低血漿VitB₁₂水平，還導(dǎo)致血漿MMA顯著增加，血漿MMA增加與神經(jīng)病變?cè)u(píng)分相關(guān)，提示臨床應(yīng)用二甲雙胍時(shí)應(yīng)監(jiān)測(cè)Vit B₁₂。

Objective To investigate the effects of metformin on Vit B₁₂, MMA and neuropathy in type 2 diabetic patients.Methods A total of 60 insulin-treated patients with type 2 diabetes were enrolled. They were randomly divided into the observation group and the control group, then they were treated with metformin or placebo for 52 months. We compared the level of FPG、PPPG、HbA1c、Vit B₁₂、MMA and Neuropathy Scores before and after treatment between the two groups.Results After treatment with metformin for 3 years, FPG, PPPG and HbA1c in the observation group were decreasing significantly(P<0.05), and those in the observation group were significantly lower in the control group. The scores ofneuropathy and MMA in the two groups were increasing significantly, the observation group was significantly higher than the control group (P<0.05). Meanwhile, Vit B₁₂ were decreasing significantly, the observation group was significantly lower than the control group (P<0.05).Conclusions Metformin not only reduces serum levels of B₁₂, but also increases serum MMA progressively. The increase of MMA was associated with the NPS significantly. These results suggested that monitoring of B₁₂ in users of metformin should be considered