Endocrine Abstracts

Introduction: Metformin is effective in reducing cardiovascular mortality, however may decrease vitamin B12 and folate levels, and increase levels of homocysteine. Hyperhomocysteinemia is associated with adverse impact on lipid parameters and renal function. The present study was designed to determine the effect of homocysteine lowering therapy by using group B vitamins and folate supplementations on lipid metabolism especially HDL cholesterol as well as kidney function assessed by serum creatinine, urine microalbumin (MA), albumin creatinin ratio (MaCR) and GFR in diabetic patients treated with high doses of metformin.

Methods: In a randomized, placebo-controlled study, 60 diabetic patients treated with a high dose of metformin were randomly assigned to receive daily oral supplementation with folate (1000 mcg), vitamins B12 (400 mcg) and B6 (10 mg) (Group 1) or placebo (Group 2). Metabolic parameters were measured at baseline and after 4 months folow-up.

Results: The two groups were similar at baseline in terms of metabolic parameters. After 4-months, HDL cholesterol was significantly greater in patients who received vitamin supplementation than patients in the placebo group (P<0.0001). Post-treatment vitamin B12 and folic acid levels were greater in group 1 vs group 2 (P=0.007 and P<0.0001, respectively). Hcy level decreased significantly in the treatment group from 10.0±4.4 to 7.6±2.5 mol/l, P=0.002 and did not change in the placebo group (P=0.964). In GLM model, group was significant independent predictor of endpoint HDL choleserol (P=0.018), while post-treatment LDL cholesterol did not differ by group after controlling for the other variables in the model (P=0.158). Posttreatment GFR was significantly greater in patients who received vitamin supplementation than patients in the placebo group (P<0.003). Plasma creatinine, urine protein and urine microalbumin did not differ significantly by treatment group at baseline at the end of the study. Nevertheless, within the vitamin -treated group, MaCR dcreased from baseline (P<0.036) and did not change in the placebo group.

Conclusion: Adding B vitamins and folate supplementations to metformin was associated with beneficial effects on HDL cholesterol and renal function in diabetic patients.