Going by the results, doctors have been advised to prescribe uric acid-lowering drugs, such as allopurinol and probenecid, to otherwise healthy individuals.
Elevated levels of uric acid in the blood, called hyperuricaemia, can be caused by a diet high in purines or by impaired excretion by the kidneys. It has long been linked to kidney failure, hypertension, and cardiovascular disease. However, these results mainly came from people with metabolic abnormalities.
In the current study, Rudolf Obermayr, MD, of Sozialmedizinisches Zentrum Ost der Stadt Wien, in Vienna, Austria, and his team aimed to determine the risks of elevated levels of uric acid in healthy individuals, mainly dealing with kidney disease.
They recruited 21,475 healthy volunteers from the general Viennese population, performing an initial examination and following up with three examinations over an average of seven years.
All the participants were grouped as having normal blood levels of uric acid, slightly elevated levels, or elevated levels. During follow-up examinations, the patients' glomerular filtration rates were examined, noting that low rates indicate decreased kidney function.
It was found that with increasing uric acid groups, glomerular filtration rates decreased. After eliminating all other potential risk factors that might contribute to kidney disease, they determined that individuals in the slightly elevated uric acid group were 1.26 times as likely to develop kidney disease as those in the low uric acid group.
The risk of developing kidney disease among volunteers in the elevated uric acid group were 1.63 times greater than that of individuals in the low uric acid group.
The risk of developing new-onset kidney disease was more evident in women than in men. It also was particularly high in individuals with hypertension.
Obermayr pointed out that the finding may be important from a public health viewpoint, as the prevalence of prehypertension and hypertension in adults is approximately 60 percemt, and the prevalence of hyperuricaemia is approximately 17 percent.
He said that this study indicates that clinical trials assessing the potential of uric acid-lowering drugs for preventing kidney disease should be initiated. These agents, such as allopurinol and probenecid, are available worldwide and are safe and inexpensive.
The study will appear in the December 2008 issue of the Journal of the American Society Nephrology (JASN).