For patients with type 1 diabetes, increased levels of uric acid in the blood may be an early sign of diabetic kidney disease - appearing before any significant change in urine albumin level, the standard screening test, reports a study in the May 2008 issue of the Clinical Journal of the American Society of Nephrology.
The results raise the possibility that treatments to reduce uric acid might slow the decline of renal function in patients with diabetes. "Thus we have the hope of having a means to thwart the loss of kidney function while function is still in a relatively preserved stage," comments Dr. Elizabeth T. Rosolowsky of Joslin Diabetes Center, Boston.
The researchers measured serum uric acid concentration in 675 patients with type 1 diabetes. On screening tests, 311 patients had small amounts of the protein albumin in the urine. This result—called microalbuminuria—is generally regarded as a harbinger of kidney function loss in diabetic kidney disease (nephropathy). The other 364 patients had normal urine albumin levels.
None of the patients had higher levels of albumin (albuminuria) representing more advanced diabetic nephropathy. Nevertheless, one in five had some impairment of kidney function on a standard test, the glomerular filtration rate. "Our research showed that loss of kidney function takes place even in the absence of albuminuria in patients with type 1 diabetes," says Dr. Rosolowsky.
In contrast, the serum uric acid level was consistently related to kidney function—the higher the uric acid, the lower the kidney function. "The serum concentration of uric acid in these patients varied in a manner consistent with its having played a role in this early loss of kidney function," according to Dr. Rosolowsky.