Abstract
An elevated total homocysteine (tHcy) plasma concentration is associated with increased morbidity and mortality due to cardiovascular disease in the general population and in patients with impaired renal function. The prevalence of hyperhomocysteinaemia (plasma levels above 15 μmol/l) in the general population is less than 5% and can be as high as 50% in patients with vascular disease. In patients with renal insufficiency, elevated tHcy plasma levels are detected in 50 - 100% of the patients. Total homocysteine plasma levels can be lowered or normalised by folic acid and/or vitamin B6 and vitamin B12 supplementation. In patients with advanced chronic renal insufficiency or end-stage renal disease, hyperhomocysteinaemia is partially resistant to folic acid or vitamin therapy. However, higher tHcy plasma levels may also reflect tissue damage and the increase in Hcy after an acute incident such as stroke or myocardial infarction may be necessary for tissue repair mechanisms. This implies, that lowering tHcy may even be harmful to some patients. Currently, prospective studies are underway to clarify whether folate supplementation, with or without additional other vitamins, improves cardiovascular disease morbidity and mortality in the general population, as well as in renal failure patients. While population-wide screening for and treatment of hyperhomocysteinaemia is generally not recommended, treatment of high risk patients may be considered.