Long-term treatment with metformin in type 2 diabetes and methylmalonic acid: Post hoc analysis of a randomized controlled 4.3 year trial

Mattijs Out, Adriaan Kooy, Philippe Lehert, Casper A. Schalkwijk, Coen D. A. Stehouwer*

*Bijbehorende auteur voor dit werk

    OnderzoeksoutputAcademicpeer review

    49 Citaten (Scopus)


    Aims: Metformin treatment is associated with a decrease of serum vitamin B12, but whether this reflects tissue B12 deficiency is controversial. We studied the effects of metformin on serum levels of methylmalonic acid (MMA), a biomarker for tissue B12 deficiency, and on onset or progression of neuropathy.

    Methods: In the HOME trial, 390 insulin-treated patients with type 2 diabetes were treated with metformin or placebo for 52 months. In a post hoc analysis, we analyzed the association between metformin, MMA and a validated Neuropathy Score (NPS).

    Results: Metformin vs placebo increased MMA at the end of the study (95%CI: 0.019 to 0.055, p = 0.001). Mediation analysis showed that the effect of metformin on the NPS consisted of a beneficial effect through lowering HbAlc (-0.020 per gram year) and an adverse effect through increasing MMA (0.042 per gram year), resulting in a non-significant net effect (0.032 per gram year, 95% CI: -0.121 to 0.182, p = 034).

    Conclusion: Metformin not only reduces serum levels of B12, but also progressively increases serum MMA. The increase of MMA in metformin users was associated with significant worsening of the NPS. These results provide further support that metformin-related B12 deficiency is clinically relevant. Monitoring of B12 in users of metformin should be considered. (C) 2017 Elsevier Inc. All rights reserved.

    Originele taal-2English
    Pagina's (van-tot)171-178
    Aantal pagina's8
    Nummer van het tijdschrift2
    StatusPublished - feb.-2018

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