A study of patients with renal failure has found a significant link between lower levels of magnesium in the blood and vascular calcification, a condition associated with an increased risk of cardiovascular and other diseases.1 Ishimura and colleagues at the Osaka City University Graduate School of Medicine examined 390 Japanese patients who had been on haemodialysis for more than 3 months, using X-rays of the hand to assess calcium salt deposits in their arteries. They found that those without the deposits also had higher levels of magnesium in the blood, but that a ‘1 mg decrease in serum magnesium increased the risk for vascular calcification by 71.6%’.

A number of previous studies have found that high levels of phosphate and calcium in the blood are a risk factor for vascular calcification, but Ishinura et al’s paper was the first to assess the link between magnesium and the condition in a large group of patients. The authors were unsure of the reasons for the link, but pointed out that in patients without kidney disease the association between low levels of magnesium, cardiovascular disease and the build-up of plaque on artery walls is well documented.

The authors suggested that supplementary magnesium for renal failure patients would have a protective effect against vascular calcification and improve patient outcomes. One option is to increase levels during haemodialysis but, given the complex interaction between various elements in the bodies of these patients, more studies would be needed to find the optimal concentration.

1. Ishimura E, Okuno S, Kitatani K et al. Significant association between the presence of peripheral vascular calcification and lower serum magnesium in hemodialysis patients. Clin Nephrol. 2007 Oct;68(4):222-7.

‘Both early- and late-stage renal failure on the rise, according to studies’

A study in the Journal of the American Medical Association has found that the percentage of the population with the earlier stages of chronic kidney disease (CKD) has increased in the US population since the early 1990s. Coresh et al1 compared two surveys of the US population, one between 1988 and 1994 and the other between 1999 and 2004. They calculated the rates of stage 1–4 CKD by examining data on two established indications of renal failure – albuminuria, the presence of protein in the urine, and glomerular filtration rate, the ability of the kidneys to filter and remove waste products.

In the earlier period 10% of US citizens could be said to have chronic kidney disease, but ten years later the figure had risen to 13%. The authors suggested increased diabetes and hypertension in the US population, as well as a higher average body mass index, partly accounted for the change. Worryingly, only 11.6% of men and 5.5% of women with stage 3 were aware that they had weak or failing kidneys.

Another study presented at the American Society of Nephrology’s annual meeting in San Francisco suggested that end-stage renal failure (ESRD), the most severe stage of CKD, is also on the rise. Using data from the United States Renal Data System (USRDS) along with US census projections, David Gilbertson and Alan Collins predicted that the prevalence of ESRD could rise by up to 60% by 2020.2 Gilbertson and Collins’ projections suggest that in 2020 the US could have 784,613 patients with stage 5 CKD, nearly a third of a million more than it had in 2005.

1. Coresh J, Selvin E, Stevens LA, Manzi J, Kusek JW, Eggers P, Van Lente F, Levey AS. Prevalence of chronic kidney disease in the United States. JAMA. 2007 Nov 7;298(17):2038-47.
2. Gilbertson DT, Collins AJ. Projecting the ESRD Population to 2020 [SA-FC046]. Abstract presented at the American Society of Neprhology’s Renal Week 2007, San Francisco.