Abnormalities of homocysteine and B vitamins in the nephrotic syndrome

IntroductionThe nephrotic syndrome is associated with heightened risk for arterial and venous thrombosis. Multiple derangements of hemostasis and acquired risk factors such as hyperlipidemia and hypertension contribute to this risk. The prevalence in the nephrotic syndrome of high circulating levels of homocysteine and of low levels of the B vitamins that are involved in its metabolism, which may play a role in thrombosis, is not well defined.Materials and methodsIn 84 patients with nephrotic syndrome and 84 sex- and age-matched controls, hemostasis variables and the circulating levels of total homocysteine (tHcy), vitamin B6, B12 and folates were measured.ResultstHcy levels were higher, vitamin B6 and vitamin B12 levels were lower in nephrotic patients than in controls. The association of low vitamin B6 levels with the nephrotic syndrome was independent of any other alteration associated with the disease. Eighty-two percent of patients with the nephrotic syndrome had vitamin B6 levels falling in the lowest quartile of the normal distribution. Antithrombin deficiency, factor V Leiden, antiphospholipid antibodies, hypertension, dyslipidemia, were more frequent in patients with the nephrotic syndrome than in controls.ConclusionsPatients with the nephrotic syndrome have multiple risk factors for thrombosis. We report that they frequently have low circulating levels of vitamin B6, which associate with a heightened risk for venous and arterial thrombosis.