LONDON, Ontario—Among patients with diabetic nephropathy, high doses of B vitamins compared with placebo resulted in a greater decrease in the glomerular filtration rate (GFR) and an increase in vascular events, according to a recent Canadian study (JAMA. 2010;303(16):1603-1609). A multicenter, randomized, double blind, placebo-controlled trial (Diabetic Intervention with Vitamins to Improve Nephropathy [DIVINe]) at five university medical centers in Canada conducted between May 2001 and July 2007 of 238 participants who had type 1 or 2 diabetes and a clinical diagnosis of diabetic nephropathy received a single tablet of B vitamins containing folic acid (2.5 mg/d), vitamin B6 (25 mg/d), and vitamin B12 (1 mg/d), or matching placebo.
The mean (SD) follow-up during the trial was 31.9 (14.4) months. At 36 months, radionuclide GFR decreased by a mean (SE) of 16.5 (1.7) mL/min/1.73 m2 in the B-vitamin group compared with 10.7 (1.7) mL/min/1.73 m2 in the placebo group. There was no difference in requirement of dialysis. The composite outcome occurred more often in the B-vitamin group. Plasma total homocysteine decreased by a mean (SE) of 2.2 (0.4) µmol/L at 36 months in the B-vitamin group compared with a mean (SE) increase of 2.6 (0.4) µmol/L in the placebo group.
