Vitamina B, función renal y eventos vasculares

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Med Alert
May 17, 2010

High-dose B-vitamins worsen renal function and increase vascular events in patients with diabetic nephropathy

Summary <> Among patients with diabetic nephropathy, high doses of B vitaminsvs placebo resulted in a greater decrease in radionuclide glomerular filtration rate (GFR) and an increase in vascular events.

Basis for Study <> Approximately 40% of the estimated 21 million patients with diabetes in the US develop overt nephropathy. Hyperhomocysteinemia is frequently observed in these patients. The authors sought to determine whether B-vitamin therapy, which has been shown to lower the plasma concentration of homocysteine, could slow the progression of diabetic nephropathy and prevent vascular complications.

Detailed Summary of Study <> In a multicenter, randomized, double-blind, placebo-controlled trial, 238 participants with type 1 or 2 diabetes and 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. Primary outcome was the change in radionuclide GFR between baseline and 36 months. Secondary outcomes were dialysis and a composite of myocardial infarction, stroke, revascularization, and all-cause mortality. Plasma total homocysteine was also measured.

Results/Body <> At 36 months, the B-vitamin group had a more rapid decrease in renal function, measured by radionuclide GFR: mean (SE) of 16.5 (1.7) mL/min/1.73 m2 vs 10.7 (1.7) mL/min/1.73 m2 in the placebo group (mean difference, -5.8). The 36-month risk of a composite outcome, including MI, stroke, revascularization, and all-cause mortality was doubled in the B-vitamin group. Plasma total homocysteine was significantly lowered in treatment group.

Sources & Other Links <> House AA, Eliasziw M, Cattran DC, Churchill DN, Oliver MJ, Fine A, Dresser GK, Spence JD. Effect of B-vitamin therapy on progression of diabetic nephropathy: a randomized controlled trial. JAMA. 2010;303(16):1603-09.

Comentario del autor del blog:  les recomiendo leer los siguientes artículos acerca del uso de las vitaminas
- Suplementación con altas dosis de vitamina E está asociado con incremento de todas las causas de mortalidad . ACP J Club. 2005 Jul-Aug;143(1):1.
- Altas dosis de suplementos de Vitamina E (> o =400 IU/d) puede incrementar todas las causas de mortalidad y deben de ser evitadas. Ann Intern Med. 2005 Jan 4;142(1):37-Vitamina D y reducción de la mortalidad

- Los individuos asignados al azar a vitamina D presentaron una reducción del 7%, estadísticamente significativa, de la mortalidad por todas las causas. Archives of Internal Medicine 167(16):1709-1710, Sep 2007 46. Epub 2004 Nov 10.
- Un estudio reciente de la salud de los médicos no encontró beneficios de la Vitamina C y la E en la prevención de eventos cardiovasculares comparado con placebo. Sesso HD, Buring JE, Christen WG, et al. Vitamins E and C in the prevention of cardiovascular disease in men. The Physicians' Health Study II randomized controlled trial. JAMA 2008;300:2123-33.