Routine blood and urine tests may help to predict the risk of end-stage renal disease developing between middle age and old age, according to an article published online April 12 by the Journal of the American Society of Nephrology.

Areef Ishani, MD, and his American colleagues analyzed data on nearly 13,000 men enrolled in a long-term study of cardiovascular disease prevention. At the start of the study in 1972-1975, the men were 35 to 57 years old and at high risk for heart disease but without existing coronary heart disease. Follow-up data through 1999 were analyzed to determine whether common laboratory tests and other factors could help to identify patients at high risk for eventual end-stage renal disease.

Over 25 years, 1.7 percent of men developed end-stage renal disease or died of kidney disease. On a standard dipstick test for proteinuria, men who had more than a trace amount of protein in their urine in middle age had three times the risk of end-stage renal disease at follow-up. For those with a stronger positive result, risk was more than 15 times higher than in peers with a normal result.

The estimated glomerular filtration rate also predicted long-term risk for renal disease. When estimated rate was abnormally low, risk for later end-stage renal disease more than doubled.

The risk of end-stage renal disease was especially high when both the dipstick test and estimated glomerular filtration rate were abnormal---41 times higher than in men with normal results on both tests.

Several other factors predicted risk, including age, smoking, blood pressure, low levels of high-density lipoprotein cholesterol, and blood glucose level.
The rate of end-stage renal disease is rapidly increasing. Doctors would like to identify factors associated with its development, with the hope that early intervention will prevent the disease and its related complications such as cardiovascular disease and death.

"Both tests are very easy to perform, and are commonly done in clinical practice," said Ishani. "Future studies can determine whether intervening on these factors can prevent the development of end-stage renal disease."