WASHINGTON - PATIENTS with diabetic nephropathy, kidney disease caused by diabetes and treated with high doses of vitamin B, suffered rapid deterioration of the kidneys, a study released on Tuesday found.

Diabetics in addition to kidney function loss also were affected by higher rates of heart attack and stroke than those who took a placebo, according to the clinical research in the April 28 edition of the Journal of the American Medical Association (JAMA). Diabetic nephropathy affects the network of tiny blood vessels in the glomerulus, a structure in the kidney made of capillary blood vessels, which is needed to filter blood.

Despite a range of treatments to curb the progression of the disease, about 40 per cent of the 21 million Americans who have diabetes develop diabetic nephropathy so a new approach to treatment is needed, the authors of the study said. Observational studies have shown a link between high concentrations of plasma total homocysteine and the risk of developing diabetic nephropathy, retinopathy, and vascular diseases, including myocardial infarction and stroke. B-vitamin therapy meanwhile - using folic acid, vitamin B6, and vitamin B12 - has been shown to lower the plasma concentration of homocysteine.

Andrew House of the University of Western Ontario and J. David Spence of the Robarts Research Institute in London, Ontario ran a study to see if B-vitamin therapy would slow progression of diabetic nephropathy and prevent vascular events in 238 patients with type 1 or 2 diabetes. The placebo-controlled trial was conducted at five university medical centers in Canada between May 2001 and July 2007.

Patients received single tablet of B vitamins with folic acid (2.5 mg/d), vitamin B6 (25 mg/d), and vitamin B12 (1 mg/d), or matching placebo. After they were followed for an average of 31.9 months, researchers found patients treated with vitamin B had a faster rate of reduction of kidney filtering hence kidney function compared to those on a placebo course.

Patients with the diabetic nephropathy additionally had a higher rate of heart attack and stroke than patients who received placebo. 'In addition to the personal burden, the societal burden of diabetic nephropathy is enormous, exceeding US$10 billion (S$13.7 billion) in annual medical expenditures,' the authors stressed. -- AFP