WEDNESDAY, April 12 (HealthDay News) -- Simple blood and urine tests in middle age may help predict a person's risk of developing end-stage kidney disease over the next 25 years.

U.S. researchers say the tests include the urine "dipstick" test (which detects protein in urine) and a blood test to estimate kidney function called the "estimated glomerular filtration rate" (eGFR).

For this study, a team from the Minneapolis Veterans Affairs Medical Center analyzed data on nearly 13,000 men enrolled in a long-term study of cardiovascular disease prevention. The men were 35 to 57 years old when the study began in 1972-1975. Follow-up data was available through 1999.

Over 25 years, 1.7 percent of the men developed end-stage renal disease (ESRD) or died of kidney disease.

Men who had more than a trace amount of protein in their urine in middle age -- as detected by the dipstick test -- had triple the risk of ESRD at follow-up. Men with an even stronger positive result for protein in the urine were 15 times more likely to develop ESRD.

The study also found that ESRD risk more than doubled in men with abnormally low eGFR function.

Men with abnormal readings on both the dipstick test and eGFR were 41 times more likely than men with normal results on both tests to suffer ESRD, the researchers noted.

Age, smoking, blood pressure, low levels of HDL ("good") cholesterol, and blood sugar levels were other factors that predicted ESRD risk, the study authors said.