Therefore , although the overall effect of metformin on the concentration of serum Hcy was neutral , our results suggested that metformin could increase the concentration of Hcy when exogenous B-group vitamins or folic acid supplementation was not given
The aim of this systematic review is to assess whether metformin could change the concentration of serum homocysteine ( Hcy ) with and without simultaneous supplementation of B-group vitamins or folic acid .
Association of Metformin, Elevated Homocysteine, and Methylmalonic Acid Levels and Clinically Worsened Diabetic Peripheral Neuropathy
OBJECTIVE The severity of peripheral neuropathy in diabetic patients varies for unclear reasons . Long-term use of metformin is associated with malabsorption of vitamin B12 ( cobalamin [ Cbl ] ) and elevated homocysteine ( Hcy ) and methylmalonic acid ( MMA ) levels , which may have deleterious effects on peripheral nerves . The intent of this study was to clarify the relationship among metformin exposure , levels of Cbl , Hcy , and MMA , and severity of peripheral neuropathy in diabetic patients . We hypothesized that metformin exposure would be associated with lower Cbl levels , elevated Hcy and MMA levels , and more severe peripheral neuropathy . RESEARCH DESIGN AND METHODS This was a prospect i ve case-control study of patients with type 2 diabetes and concurrent symptomatic peripheral neuropathy , comparing those who had received > 6 months of metformin therapy ( n = 59 ) with those without metformin exposure ( n = 63 ) . Comparisons were made using clinical ( Toronto Clinical Scoring System and Neuropathy Impairment Score ) , laboratory ( serum Cbl , fasting Hcy , and fasting MMA ) , and electrophysiological measures ( nerve conduction studies ) . RESULTS Metformin-treated patients had depressed Cbl levels and elevated fasting MMA and Hcy levels . Clinical and electrophysiological measures identified more severe peripheral neuropathy in these patients ; the cumulative metformin dose correlated strongly with these clinical and para clinical group differences . CONCLUSIONS Metformin exposure may be an iatrogenic cause for exacerbation of peripheral neuropathy in patients with type 2 diabetes . Interval screening for Cbl deficiency and systemic Cbl therapy should be considered upon initiation of , as well as during , metformin therapy to detect potential secondary causes of worsening peripheral neuropathy
Therefore , although the overall effect of metformin on the concentration of serum Hcy was neutral , our results suggested that metformin could increase the concentration of Hcy when exogenous B-group vitamins or folic acid supplementation was not given
The aim of this systematic review is to assess whether metformin could change the concentration of serum homocysteine ( Hcy ) with and without simultaneous supplementation of B-group vitamins or folic acid .